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Tissue sampling is one of the important procedures for making slices. According to the specific requirements of teaching, scientific research and external inspection, the tissue is taken from human or animal, and the location and method of sampling are determined. Specific requirements are as follows: 1. Fresh materials to ensure the original morphological structure 2. Size of tissue block The ideal volume of tissue block is 2.0x2.0x0.3cm, so that the fixative can rapidly and evenly penetrate into the tissue 3. Do not squeeze the tissue block. The blade of the tissue block should be sharp. Do not clamp the tissue too tightly to avoid deformation of the tissue and cells due to extrusion. 4. Standardize the sampling position. The sampling shall be accurate according to the anatomical position, and standardized according to the requirements. 5. Selecting the section of tissue block determines the direction of its section according to the structure of each tissue. Longitudinal and transverse sections are often the key to display the morphological structure of the tissue. 6. Keep the material clean. If there is dirt, mucus, etc. in the tissue block, it can be cleaned with water before being put into the fixing solution. 7. Keep the original shape of the tissue. After fixing the fresh tissue, most of the tissue will shrink, sometimes even completely deform. Therefore, flatten the tissue to maintain the prototype as much as possible.

In our daily life, we are exposed to all kinds of plants, especially seed plants, including pine, fir, cypress, ginkgo, and all kinds of flowering and fruiting plants. To systematically study plant classification, we can use plant specimens. Plant specimens can be divided into the following categories according to the purpose of use (1) Phylogenetic specimen: The purpose of preparation is to observe and study the life history of a plant, that is, the growth of a plant at each stage from seed germination to growth, development, flowering and fruiting. It is commonly used in biological teaching, introduction, cultivation and scientific research. (2) Whole specimen: usually used to identify plants, scientific names and Chinese herbal medicines. This specimen is also used for vegetation survey in an area. For example, investigate the plant resources of a school or mountain. The roots, stems, leaves and other vegetative organs of higher plants are one of the bases for identifying plants, but they are often different due to different growth environments. The flowers and fruits have relatively stable heredity, which can best reflect the inherent characteristics of plants, and are an important basis for identifying and identifying plants. When collecting specimens, try to collect specimens with complete roots, stems, leaves, flowers and fruits. Herbs should also be dug up underground. The shape and arrangement of sporangia, rhizome, scales and indumentum are important taxonomic characteristics of ferns, which should be paid attention to when collecting. The whole specimen is often made into wax leaf specimen and primary color immersion specimen. (3) Anatomical specimen: The purpose of preparation is to observe and study the internal organizational structure of a plant organ. For example, dissect the bulb of onion to observe the structure of base plate, bud, scale leaf, fibrous root, etc. The lateral membrane placentation and seed bearing position of cucumbers were observed by transverse dissection; The peach flower was dissected longitudinally to observe its various parts and morphology. To collect this kind of specimen, you only need to select a healthy and representative organ, instead of collecting the whole branch. Anatomical specimens are usually made into antiseptic impregnated specimens. (4) Comparison specimen: The comparison specimen is mainly used to compare the similarities and differences of an organ of different plants. For example, to compare the seed morphology of dicotyledons and monocotyledons, it is necessary to collect the mature fruits of rape, soybean, cucumber, tomato, etc., remove the peel, dry the seeds, and also collect the fruits of wheat, rice, and corn for comparison. The comparison specimen can be made into wax leaf specimen or air dried specimen, and the fruit soaked with primary color is better.

Proper maintenance of the microscope can prolong the service life of the microscope. Today, I will explain how to clean the optical glass. There are two types of glass surface cleaning: atomic level cleaning surface and process technology cleaning surface. Atomic level cleaning is required for special scientific applications because it needs to be carried out under ultra vacuum conditions. Generally, only the clean surface in process technology is required to meet the requirements for product processing. Optical glass is used for lenses, prisms, lenses, etc. of instruments. In manufacturing and use, it is easy to get greasy dirt, water wet dirt, fingerprints, etc., which affects imaging and light transmittance. To clean the optical glass, different cleaning agents, tools and methods should be selected according to the characteristics and structure of the dirt. Clean the lens coated with antireflection film, such as camera, slide projector and microscope lens, and use about 20% alcohol and 80% ether as cleaning agent. When cleaning, use a soft brush or cotton ball dipped with a small amount of cleaning agent to make a circular movement from the center of the lens outward. Do not immerse such lenses in cleaning agent for cleaning, and do not wipe them hard when cleaning them, otherwise the antireflection film will be damaged and the lens will be damaged. There are many methods to clean the glass surface, and one of them can be selected or combined according to the original pollution degree of the glass surface, the subsequent glass surface treatment process and the purpose of the final product. The oil mist, water wet mist and oil-water mixed mist on the optical glass can also be cleaned by using the cleaning agent, and the cleaning method is similar to that of the lens. Mold on the surface of optical glass is a common phenomenon. When the optical glass is mouldy, the light will scatter on its surface, making the image blurred, and in serious cases, the instrument will be scrapped. The reason for the mildew of optical glass is that there are microbial spores on its surface. When the temperature and humidity are appropriate and "nutrients" are needed, it will grow rapidly and form mildew spots. It is particularly important to make the optical glass anti mildew and antifouling. Once mildew occurs, it should be cleaned immediately. Pay attention to dryness.

The plant soaking specimen is to store fresh plant materials in the solution prepared by chemicals, so that the original color and shape of plants can be observed. The plant soaking specimen has a good preservation effect and a long preservation time, restoring the original bright color of plants. It has many advantages, and provides an essential scientific basis for plant research. How does the soaking specimen maintain the original color of plants? The reason why plants are green is that chloroplasts of plants contain chlorophyll. Chlorophyll is a complex organic compound. There is a metal magnesium atom in the center of its molecular structure. The reason why chlorophyll is green is that it contains the core structure of magnesium atom. If you want to keep the original green in plants, you need to replace magnesium ions in chlorophyll with copper ions. Its method is to use acid to separate magnesium from chlorophyll molecules. At this time, because chlorophyll lacks magnesium, the plant becomes brown. Then replace the core magnesium of chlorophyll molecule with copper. The structure of chlorophyll molecule with copper atom as the core is very stable, is not easy to decompose and destroy, and is not soluble in alcohol or formalin. Therefore, plant samples treated in this way can be preserved green for a long time in the preservation solution.

Wax leaf specimen, also known as pressed specimen, is the most common kind of plant specimen. It is crucial to correctly identify plant species to make specimens that can maintain the natural and true morphological characteristics of plants. The advantage of wax leaf specimens is that they can be preserved for a long time. The collection of wax leaf specimens with a long history in the world can even be traced back to around the 16th century. However, the wax leaf specimen made by this traditional method has faded due to the destruction of chlorophyll and anthocyanins in the plant. In addition, because the wax leaf specimen uses the pressing process, the final product presents a flat state that has been faded into brown yellow and fixed on the table paper, which is not dominant from the aesthetic point of view. The suppression process is the key to combine the original ecological characteristics of plants with artistic beauty. The on-site pressing effect is the best after collecting the specimen, but the actual operation is time-consuming and labor-intensive, which is difficult. Therefore, the plant can be put into the self sealing plastic bag. In order to prevent extrusion deformation, it is necessary to inflate the belt, mark the corresponding collection information and bring it back for pressing after sealing. For plants that are thin and vulnerable to water loss, they must be suppressed on site to accurately describe plant characteristics. When placing the plants in the specimen folder, try to spread the roots, branches, leaves, flowers and fruits, and turn them over partially to better understand the specimen characteristics.

The use of biological specimens is diverse and plays an important role in scientific research and biological teaching. In addition, they are also of great value in drawing, exhibition, viewing, etc. For scientific research, biological specimens can provide direct, reliable, accurate and intuitive objects and data for scientific research, which is of great significance for studying the life, growth and development laws of animals and plants. For example, when plant taxonomists systematically classify various plants, they must take plant specimens as the main basis, analyze the differences of research objects in root, stem, leaf, flower, fruit, seed and other aspects through plant standards, so as to correctly judge their characteristics, so as to accurately identify each plant. In teaching, biological specimens can make the knowledge explained by teachers more intuitively displayed, thus deepening students' understanding and cognition. For example, when visiting the Animal and Plant Museum, we can see many precious animal and plant specimens. The exhibition of these biological specimens provides the majority of young people with the conditions to learn biological knowledge, improves their interest in learning, and also enhances the public's understanding of nature, and establishes a correct concept of animal and plant protection. Biological specimens are the most valuable permanent records in human natural heritage, and play an irreplaceable role in scientific research, scientific knowledge popularization and human daily life. With the development of the times, human beings have made a transition in the use of natural resources, and the environment has gradually deteriorated today. Preserving biological species in the form of specimens is also of great significance for future research on the course of biological development and evolution.

In the experimental class, we have all used biological slides, and we know that biological slides can help us to better study and research, but there are inevitably some problems in the process of making biological slides. Now let's understand what problems will occur in the process of making biological slides. 1. Dehydration, transparency, too long wax soaking time and too high temperature may cause tissue brittleness. In addition, the texture of the tissue itself may also cause tissue brittleness. You can try to cut while blowing air to the wax slice, which may be relieved. 2. The knife is not sharp, the knife angle is too large, and the glass slide is too thick, which may cause the glass slide to roll up. 3. If the blade is uneven, the slide knife is not straight, and the slide knife is not parallel to the wax block, the wax may be bent. 4. If the knife is not clamped with the knife base and wax block, the thickness will be uneven if the tissue is too hard, and the slide machine spindle is too forward, or the slide machine has been worn. 5. The cracks on the glass slide may be caused by the knife gap, impurities in the paraffin, calcification, bone fragments or wired knots in the tissue, or cotton paper fibers. 6. Poor tissue dehydration may lead to the phenomenon that the glass slides are not connected, cannot be cut off, the glass slides are very thick, or the wax blocks behind the glass slides are white, invaginated, etc. There are still many problems in the actual operation. If you are interested in this aspect, you can follow us for more information.

To make a good frozen section, ensure the quality of the section, and at the same time improve the accuracy of rapid pathological diagnosis during the operation, it has a great relationship with the understanding and selection of the frozen section machine. The freezing slicer is composed of a slicing device and a refrigeration system. Generally, a complete freezing slicing system is composed of a host machine (freezer box, sample head, quick freezing table, etc.), a tool holder, and a blade. How to standardize the operation of the frozen slicer? Let's have a look 1. First, check whether the instrument is firmly and stably placed, whether the connection between the power plug and the socket is reliable, and whether the grounding is good. A certain gap is left around to facilitate ventilation and heat dissipation, and whether the voltage is normal. 2. Turn on the main switch of the power supply, check/set the temperature of the freezer, the temperature of the cold table, the temperature of the sample head, and the slice thickness, and enter the regular interface (generally, this machine is powered on for 24 hours, and is in the normal startup state, so as long as the cold table refrigeration is started at work and turned off at work). 3. Slicing procedure: put the "sampled" specimen with embedding agent on the sample head, place it on the quick freezing table for "quick freezing", lock the "slicing hand wheel". After a while, fix the frozen specimen with the sample clamp, repair the specimen first, then slice and patch. 4. Immerse the patch into "acetic alcohol solution" to "fix". 5. The cut samples shall be numbered and stored for standby or used in the downstream process. 6. Shutdown procedure - lock the hand wheel, clean the freezer, open the door of the freezer, and cut off the power switch. This machine is a continuous working machine, which is powered on continuously. Generally, it does not shut down. When it is not used for a short time, turn off the refrigeration of the cold table, and set the temperature of the freezer above 0 ℃ to stop.

(1) The quality of the materials will directly affect the quality of the slices. When taking materials, doctors should have a sharp material knife earlier, so as to avoid dragging the material knife back and forth, and it is better to cut in parallel with the fiber as much as possible when taking materials; (2) Fixation is a part of the work of the technical room, and also an irremediable part of the whole production process. Fixation is to prevent tissue cells from autolysis and corruption, prevent the decomposition of proteins by enzymes in cells, and keep their original structure similar to life (3) Water washing after fixation is usually ignored by many people, and incomplete washing is easy to cause poor color of the supporting plate and dyeing; (4) Dehydration is to use a dehydrator to replace the water in the tissue, which is conducive to the penetration of organic solvents. Whether the dehydration is complete or not is directly related to whether the tissue can be fully transparent, and excessive dehydration is easy to cause brittle tissue; (5) If you want to cut a slice well, you should have a sharp slicing knife earlier. Grinding knife is a relatively basic technology for slicing technicians. The quality of knife grinding is directly related to the quality of the slice; (6) The dyeing time shall be determined according to the old and new fuel, temperature, and type of chips. The chips can be blued with warm water or tap water and washed fully to prevent fading caused by hydrochloric acid residues; (7) The gum on the cover sheet shall not be too thin. When sealing the sheet, the gum shall be evenly filled with the cover sheet and the gum shall not overflow. The tissue shall be completely covered without bubbles and labeled. The label must be pasted on the left or right side of the slide. The number can be printed only after it is clearly written

Through small biological slices, we can understand biological characteristics. Biological teaching slice has important value in biological teaching and plays a role as an intuitive teaching tool. Paraffin section is also called permanent section, which is mainly suitable for the section of various plant tissues. The thickness of the section is easy to control, the clarity is good, and it can be made into continuous sections, which are easy to preserve for a long time. The manufacturer of paraffin slices tells you how to preserve plant paraffin slices. Put the observation material in a specific fixative as soon as possible, kill its cells quickly, and try to keep it in its natural state of life. After the material is fixed, it needs to be preserved for use. In this process, the structure of the material is required not to change. The commonly used preservation solvent is 70% alcohol solution, which can keep ordinary materials from getting bad for a long time. It is also required to be stored in the refrigerator. Use of alcohol concentration: fix weak and tender plants with low concentration alcohol, such as 50%; Use 70% alcohol to fix older or harder materials. If plant embryo materials are fixed, the formula can be modified to 50% alcohol 89ml+glacial acetic acid 5ml+formaldehyde 40% for storage The four sides of the biological tissue slice are fixed without shrinkage and deformation, and the smooth surface of the plexiglass on both sides protects the two sides of the fixed slice, which is convenient for observing the internal structure of the biological tissue.

Fluorescence microscope is a basic tool of immunofluorescence cytochemistry. It is composed of light source, filter plate system, optical system and other major components. Observe with ordinary optical microscope. Slide specimens are usually stained with hematoxylin eosin, sometimes with special staining. First of all, the optical microscope should keep the natural state of the biological materials as far as possible to avoid artifacts, deformation and distortion, so the biological materials must be fixed; The film must be thin and transparent before it can be imaged under the optical microscope. In addition to cutting the material into thin slices or dispersing it by light pressing or other means, other methods must be used to make it transparent and dyed, so as to better observe the details of the structure. In fact, all biological materials can obtain specimens that meet the requirements in thickness and transparency through paraffin embedding, slicing (or smearing), adhesion, wax dissolution, transparency and other processes, and then obtain a certain degree of contrast through dyeing procedures. The biological slice is often pasted on the glass slide with a standard size of 26x76mm and a thickness of 1.1 ^ - 1.3mm. The two sides of the glass slide should be parallel planes. The requirement for the thickness of the glass slide is not very strict, but when its thickness exceeds the free working distance of some collectors with higher correction degree, the thickness of the glass slide becomes important for focusing the light source and forming the image of the field stop on the object plane. In this case, a glass slide with a thickness of 0.9 ^ - 1.0mm is appropriate.

Fluorescence microscope is a point light source with high luminous efficiency, which emits light of a certain wavelength (such as ultraviolet light 3650 or violet blue light 4200) as excitation light through the filter color system. After excitation, fluorescent substances in the specimen emit fluorescence of different colors, and then observe through the amplification of the objective lens and eyepiece. In this way, under the strong contrast background, even the fluorescence is very weak, it is easy to recognize, and the sensitivity is high. It is mainly used for the study of cell structure and function and chemical composition The light source of a fluorescence microscope does not act as a direct illumination, but as an energy source for stimulating the fluorescent material inside the specimen. The reason why we can observe the specimen is not the illumination of the light source, but the fluorescence phenomenon presented by the fluorescent substance in the specimen after the absorption of the excited light energy. It can be seen that the main characteristic of fluorescence microscopy is that its light source can supply a large amount of excitation light in a specific wavelength range, so that the fluorescent substances in the specimen can obtain the necessary intensity of excitation light. At the same time, fluorescence microscope must have the corresponding filter system. Fluorescence microscope is a special tool for fluorescence microscopy detection, it is a kind of light microscope. In addition to the basic structure and optical amplification of optical microscopy, it also has the following unique functional requirements based on fluorescence characteristics: (1) A light source that provides enough energy to excite fluorescence. (2) with a set of color filters to adapt to the excitation spectrum required by different substances, the appropriate excitation spectrum is selected from the light source, so that the spectrum precipitated coincides with the absorption spectrum of the substance, in order to obtain the maximum fluorescence. (3))In order to obtain a weak fluorescence image, a set of cut-off color filter should also be established, which makes the required observed fluorescence go into the system for imaging, and the rest of the light waves, including the emitted light, are blocked out to improve the image lining. (4)The amplified optical system should adapt to the characteristics of fluorescence, and finally obtain a good fluorescence image with high brightness and high resolution that can be observed and photographed. (5) Safety of the instrument. The application of mercury lamp is necessary to prevent the leakage of ultraviolet light and mercury lamp explosion, to ensure the safety of electrical appliances.

For small insects such as jumpers, fleas and planthoppers, needles should not be inserted directly, but special methods should be used. 1.Double interpolation The needle size 00 is thin and short, with a sharp tip and no needle cap. It is specially used to puncture small and hard insects. The insect body was picked up with small forceps, and the specimen was punctured vertically with microneedle according to regular needle position, and inserted on a small triangular cork block or hard paper. Then insect needles above No. 1 were inserted near the bottom edge of the triangular paper, and then the insect position was fixed with a three-stage stage. The specimen and label inserted were located on the left side of the insect needle. 2.Worm interpolation Cut the cardboard into a small isosceles triangular card with bottom edge length of 0.4cm and height of 1cm. Dip the tip of an insect needle into latex and gently point it on the tip of the triangular card. Then glue the insect body with the tip of the needle and place it on the latex, and quickly withdraw the needle to avoid picking up the insect body. The key point of this operation is that there should not be too much latex on the tip of the needle. If the glued specimen needs to be upright, the insect tip can be used to stir it. Finally, the insect needle can be inserted near the bottom edge of the triangle film, and the insect position can be fixed with a three-stage stage, and the label can be inserted into the specimen box for long-term storage.

With people's research on biology, in order to observe the experimental structure, more and more experimental articles need to be sliced for experimental observation. Therefore, various biological drug experimental cutting machines have emerged. The emergence of slicing mechanisms has helped people to process various experimental samples. In order to facilitate observation of the experimental structure, people need not only to preprocess the test samples, but also to accurately slice the thickness. Slicing method is to use sharp cutting tools to cut tissue into extremely thin slices. The material must undergo a series of special treatments, such as fixation, dehydration, embedding, slicing, dyeing, etc. the process is very complicated. In the production process, it also needs to undergo a series of physical and chemical treatments, which can be reasonably selected according to the property requirements of various materials. Although the process of sectioning is cumbersome and the technology is complex, it can best maintain the normal relationship between cells and preserve the original appearance of cells for a better and longer time, so it is still the main method of making light microscopy. The existing slicers usually use manual slicing. The stability and accuracy of slicing are low, and the thickness of slicing cannot be consistent. It is a biological slicer device that is easy to operate, flexible to use, and convenient to improve the stability and accuracy of slicing. At present, there are commonly used biological tissue slicers, paraffin slicers, frozen slicers and so on. The biological tissue slicer is famous for its high accuracy and stability. It is fed by a stepping motor, has the functions of sample retraction and slice counting, and is accurately positioned on the X / Y axis of the sample head. The working principle of the slicer is relatively simple, that is, by using the sharp cutting surface of the slicer, objects and materials are cut into pieces according to the proportion or width of a point. So as to be suitable for production or pharmaceutical or other uses. The main purpose of the biological slicer is to slice materials such as medicinal materials, cell tissues and waxes, so as to facilitate their next process.

1. Pin insertion fixation Generally, fresh specimens after poison killing are collected. If the specimens are dry and hard, they should be placed in a softener for 1-2 days before the needle is inserted to fix the worms; Carefully take out the insects from the softener with tweezers and put them on the whole posture stage, avoiding touching with hands as far as possible; Select the corresponding insect needle according to the size of the insect body, insert the insect needle from the slightly right of the midline of the back of the insect body, and pass it out from the abdomen, generally making the needle in the middle of the two feet. 2. Spread one's wings and straighten one's posture Butterflies, dragonflies and other insects need to spread their wings. When spreading wings, first insert the specimen with the needle into the spreading plate carefully, so that the insect body falls into the groove, and the wings and the spreading plate are in a horizontal position. Then unfold the wings with forceps to make the trailing edge of the front wings perpendicular to the body. After the wings are adjusted to the ideal position, press the wings with the strip paper in one hand, and insert the pin around the strip paper in the other hand, but not into the wings, so that the strip paper and the wing extension plate can be closely combined to fix the wings. After spreading your wings, adjust the position of your antennae, feet and abdomen, and you'll be done. 3. Drying and storage After the specimen completes the above actions, it is almost finished. The rest is to dry the specimen. Generally, it can be dried in a constant temperature box at 50 ° C for about a week. If there is no drying box, it can also be placed in an indoor ventilated place for drying. After drying, the specimen can be stored in the specimen box. The specimen box shall be stored in a ventilated and dry place. Each specimen represents a life, which should be cherished and utilized. For example, carefully observe its shape, and try to classify and conduct other scientific research.

Paraffin section is the most widely used method in conventional histological techniques. It is not only used to observe the morphological structure of normal cells and tissues, but also the main method used by pathology, forensic medicine and other disciplines to study, observe and judge the morphological changes of cells and tissues, and has been widely used in many other disciplines and fields. The paraffin sectioning method includes the steps of material extraction, fixation, washing and dehydration, transparency, wax immersion, embedding, sectioning and pasting, dewaxing, dyeing, dehydration, transparency and sealing. Paraffin sections are usually used for HE staining or IHC. The thickness is thinner, generally 4um, the process is more complex, and the quality of the sample depends on the type and composition of different tissues, which is more dependent on the experience of the manufacturer. It needs to be constantly optimized in the experimental process to obtain the best experimental conditions.

The magnification of ordinary biological microscope can reach 1000-1600 times. Generally, microorganisms such as fungi and yeasts are relatively large, and good results can be obtained with low-power objective lens and high-power objective lens. However, to see the morphology of stained bacteria and the morphological structure of eukaryotic cells, it is best to use an oil lens. Oil lens is a kind of objective lens of microscope. The full name is oil stained objective lens. The medium of microscope objective lens includes air, water and oil. The latter two are used for high-resolution objective lens. Master the correct use of oil mirror 1. When using the oil lens, first drop asphalt on the glass slide to increase the light entering the oil lens, enhance the brightness of the visual field, and make the object image clearer. 2. Put the microscope upright on the table, and do not bend the mirror arm to tilt the stage, so as to avoid the spillage of asphalt, affecting the observation and polluting the table. 3. Aiming When natural light is used as the light source, plane reflector should be used; If artificial light is used, concave mirror shall be used. First, open the aperture and rotate the reflector to concentrate the light on the light collector. You can move the light collector up and down and scale the aperture as needed to obtain the best brightness. 4. Focus adjustment: ① Place the specimen on the stage, fix it with the specimen pusher, and move the part to be examined under the objective lens. First find out the position of the specimen with a low power lens, then raise the lens barrel, drop a drop of lens oil on the specimen to be tested, and then change the oil lens for observation. ② Turn the coarse adjuster to slowly raise the stage (or gradually lower the lens barrel) until the oil lens is immersed in the oil. At this time, the eyes should be observed from the side to avoid crushing the specimen and damaging the lens. ③ Then move both eyes to the eyepiece, observe from the eyepiece, and slowly rotate the coarse adjuster (lower the stage or raise the lens barrel) in the opposite direction. When there is a blurred object image, change to the fine adjuster, and rotate until the object image is clear. ④ After observation, the lens barrel should be raised first, and the oil lens should be twisted to one side before taking down the specimen. After the oil lens is used, the oil on the lens shall be wiped off immediately with the lens wiping paper. If the lens oil is dry on the lens, the lens can be wiped with a little xylene dipped in the lens wiping paper, and then the residual xylene can be wiped off with the dry lens paper to prevent the xylene from penetrating and dissolving the gum used to fix the lens, causing the lens to shift or fall off.

Permanent slide specimens can be kept and used permanently. Integral loading method: It is a method to seal the whole tiny organism or part of the organ to make a slide specimen. This method is generally applicable to organisms or organs with small body or a thin body, such as unicellular algae, filamentous algae, fungi, soft bryophytes, protoplasts and sporangia of ferns, epidermis of higher plants, florets and pollen grains, protozoans, wings, antennae, feet of insects, and chick embryos Attention shall be paid to: (1) When holding the slide, it should be kept flat or placed on the platform. When dripping water, the amount of water should be appropriate, so as to be just covered by the cover glass. (2) The materials shall be unfolded on the same plane without overlapping with dissecting needle or forceps. (3) When placing the cover glass, slowly cover it on the water drop from one side to prevent bubbles. (4) When dyeing, put a drop of staining liquid on one side of the cover glass, and suck it from the other side with absorbent paper to make the specimen under the cover glass uniformly colored. After coloring, use the same method, drop a drop of water, suck out the staining solution, and observe it under the microscope.

1. Different components The electron microscope has three parts, namely, the lens barrel, the vacuum device and the power cabinet. The optical microscope is mainly composed of four parts, namely, objective lens, eyepiece, reflector and condenser. 2. The imaging principle is different. An electron microscope uses an electron beam to penetrate a sample, and then magnifies the image by a lens. The optical microscope mainly uses the magnifying imaging principle of convex lens to magnify the sample. 3. The illumination source is different. The illumination source used by the electron microscope is the electron flow emitted by the electron gun; The illumination source of the optical microscope is visible light (sunlight or light). Since the wavelength of the electron flow is much shorter than the wavelength of the light wave, the magnification and resolution of the electron microscope are significantly higher than that of the light microscope. 4. The lenses are different. The objective lens for magnifying in the electron microscope is an electromagnetic lens (a ring-shaped electromagnetic coil that can generate a magnetic field at the central part); The objective lens of an optical microscope is an optical lens made of glass. There are three groups of electromagnetic lenses in the electron microscope, which are equivalent to the condenser lens, objective lens and eyepiece lens in the optical lens. 5. Different uses Because of its high resolution, the electron microscope can be used to observe the fine material structure that can not be distinguished by the ordinary microscope, and can also be used to help analyze the material composition. The optical microscope is mainly used for the observation of microscopic materials in biology and medicine, and as an experimental tool for students in teaching.

The tool microscope is a measuring instrument based on the principle that the main microscope aims at the measured object and the rectangular coordinate measurement. Because it has two kinds of installation methods of the tested parts: platform and thimble, and the optical axis of the main microscope can be tilted left and right and equipped with many accessories, it has a wide range of applications. It can accurately measure the size, angle, shape and position of various workpieces, as well as the parameters of threaded workpieces. It is one of the commonly used measuring instruments in the measuring room and workshop inspection station of machinery manufacturing enterprises. Measuring method of tool microscope: 1. Image method: the image method is a measurement method for aiming and positioning the image method by using the marks of the central microscope. During measurement, generally, the scribe line on the (meter line) reticle is used to aim at the edge of the image of the test piece, and the value is read out on the reading microscope, then the workbench is moved to aim at the other side of the image of the test piece with the same scribe line, and then the second reading is made. The difference between two readings is the measured value of the measured part. 2. Axial cutting method: the axial cutting method is a measurement method that uses the mark of the central microscope to aim and position the axis line of the measuring piece and the score line on the measuring knife. The measuring knife is an accessory of the multimeter. There is a scribe line on the surface, and the dimensions from the scribe line to the cutting edge are 0.3 mm and 0.9 mm. During measurement, place the measuring knife on the measuring knife backing plate, and the scribe surface passes through the axis of the measuring piece, and make the cutting edge of the measuring knife and the measured surface tightly contact. Aim with the corresponding meter line, measure the distance between the scribe lines of the two measuring knives, and indirectly measure the measured value of the measured piece. In order to avoid calculation in measurement, two groups of four symmetrically distributed parallel lines are engraved on both sides of the middle vertical meter line. The distance between each group of lines and the center line is 0.9 and 2.7 mm respectively, which is exactly three times the distance between the cutting edge of the measuring knife and the line of 0.3 and 0.9 mm. When aiming with a 3x objective lens, the 0.9 and 2.7 mm marks on the reticle just press the 0.3 and 0.9 mm marks on the measuring knife. At this time, the cutting edge on the measuring knife is just aimed by the middle mark of the meter line. Mainly used for pitch diameter measurement of thread.