10 STUDENTS HISTOLOGY 



The separation of tissues is frequently facilitated by means of 

 dissociating fluids, which remove the cement substance. 



SECTION CUTTING 



After having become familiar with the various elementary 

 structures of animal tissues, we proceed to the study of their 

 relation to organs. 



As the teasing process is not available with such complicated 

 structures as lung, liver, kidney, brain, etc., we resort to methods 

 of slicing i.e., section cutting. 



Sections must be made of extreme tenuity, in order that the 

 naturally opaque structures may be illuminated ~by transmitted 

 light. This becomes an easy matter with such tissues as cartilage; 

 but some, like bone, are much too hard to admit of cutting, and 

 others are as much too soft ; so that while certain tissues must be 

 softened, the majority must be hardened. Fortunately, both of 

 these conditions may be secured without in any way altering the 

 appearance or relations of the structures. Hardening processes, 

 from necessity, become a prominent feature in histological work ; 

 but we propose here to indicate some of the more useful methods 

 of section cutting, reserving the hardening processes for another 

 place. 



FREE-HAND SECTION CUTTING 



The students, when ready for this work, are provided with some 

 tissue which has been previously hardened. We will take, for 

 example, a piece of liver which has been rendered sufficiently firm 

 for our work by immersion in alcohol, and proceed to direct the 

 steps in obtaining suitable sections by the simple free-hand 

 method. 



We wish to strongly emphasize the importance of this mode of 

 cutting. A moderate amount of practice will render the micros- 

 copist independent of all appliances, save those of the most simple 

 character and which are always obtainable. 



An ordinary razor with keen edge, and a shallow dish, prefer- 

 ably a saucer, partly filled with alcohol, are required. The razor 

 best adapted to the work is concave on one side (the upper side, as 

 seen in Fig., 4) and nearly flat on the other, although this is 

 largely a matter of personal preference. 



Fig. 4 indicates the proper position of the hands in commenc- 



