(2) Sampling typical: Selecting specimens with typical structure and paying more attention in teaching. The inclusion of a variety of Shama although there are transport tissues, but if you observe the screen, screen plate, with a more suitable pumpkin stems; if you observe the hepatic lobule, British liver is taken from the pig livers; if the cochlear structure is observed, guinea pigs are not only easy to draw, but the cochlea is large, the temporal In addition, pay attention to the old and old specimens, like plant roots, stems, leaves, if too young, because of insufficient lignin, with the red-solid green double staining, not only can not dye red, instead, it is confused with phloem, thin-walled tissues, and all is solid green to cover. Of course, if the specimen is too old, then wood, thick-walled tissue prone to brittle cracking, sometimes even with the softening process, but to the cutting, wax tablets will inevitably break, the courseware selection of the appropriate old specimens is very important.
