SECTION CUTTING. IQ7 



It often happens that the sections roll up on the 

 knife. In this case they must be placed on the surface 

 of cold water and an attempt made to straighten them 

 out by careful brushing with a camel's hair brush ; when 

 fairly flat they are to be lifted up on a slide or piece of 

 paper (dipped into the water and insinuated below 

 them) and transferred to the hot water as before. But 

 the rolling of the sections may often be prevented by 

 sharpening the knife, by re-imbedding the tissues in 

 harder or in softer paraffin according to the weather, or 

 by varying the angle which the knife edge makes with 

 the glass runners of the microtome. These devices can 

 only be learnt by experience. 



When the sections are flattened out on the surface of 

 the hot water they are ready to be mounted upon slides 

 or cover-glasses ; slides are by far the best for beginners. 

 The slides (or cover-glasses) must be perfectly clean, 

 and are best kept in methylated spirit until they are 

 to be used, and the spirit not wiped off. Each slide is 

 then inserted separately into the water in an oblique 

 position and the section moved until it lies over the 

 centre ; the slide is then raised out of the water and 

 carries the section out with it. 



The excess of water is now to be removed by a piece 

 of blotting or filter paper, and the slide placed in the 

 warm incubator for a few hours. At the end of this 

 time the sections will adhere by atmospheric pressure 

 (like a boy's leather sucker to a stone) and will not 

 come off in the subsequent processes. If an incubator 

 is not at hand the slides may be placed near the fire 

 (protected from dust) and kept at the body temperature 

 or a little higher for a few hours ; the exact temperature 

 does not matter, and no harm will result if the paraffin 

 melts. 



