Microtomes 177 



himself, and, when satisfied, declared that the " history 

 of the histological investigation of the future would be 

 the history of its methods." Not only have the chemi- 

 cal substances used in preparing tissues for examina- 

 tion greatly increased since Huxley's time as an active 

 worker, but a very important method of investigation 

 has come into general use. In Huxley's time tissues 

 or animals too large or too opaque to be examined 

 microscopically as whole structures were either teased 

 by needles or were cut with a razor by hand into com- 

 paratively thick slices. The process of cutting, how- 

 ever practised the operator, was tedious and uncertain, 

 and it was almost impossible to cut a piece of tissue 

 into a series of thin slices without losing or destroying 

 considerable portions. Microtomes, with various acces- 

 sory mechanical appliances, have now been invented, 

 and by means of these not only are slices of great 

 tenuity made with ease, but there is little difficulty in 

 cutting the most delicate organism into a ribbon of 

 consecutive slices. Such new methods have made 

 almost a revolution in the study of zoology, particularly 

 of the lower forms of life and of the embryonic stages 

 of higher animals, and books written before these 

 methods became common have naturally been super- 

 seded. 



Huxley did far more for the teaching of science thau 

 the preparation of books, however useful these were. 

 He was the practical inventor of the laboratory system 

 of teaching zoological science, and all over the world 

 the methods invented by him have been adopted in 

 university laboratories and technical schools. He had 

 always declared that since zoology was a physical sci- 

 ence, the method of studying it must needs be analo- 

 gous to that which is followed in other physical sciences. 



