ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



155 



of the holder when the knife is intended to work with the whole 

 length of its edge (fastened by the fork 0'), for objects of moderate 

 hardness, and fig. 34 when it stands more transversely to the long axis 

 of the microtome (fastened by the fork 0), for parafan-imbedded 

 objects. 



For the purpose of stropping the original knives with plane-con- 

 cave surfaces, a small rod B (fig. 35) is recommended. This rod has a 

 projection at O which is inserted in a hole near t on the triangular end 



Fig. 35. 



B 



TT 



face of the knife A. The other end V of the rod is forked and is 

 fixed to the handle of the knife by the screw s. The rod and screw 

 are removed before cutting. 



The construction of the carriers for the objects has also been 

 varied according to different requests made by investigators. Fig. 36 



Fig 



shows one of the new carriers with a clamp somewhat different from 

 the original form.* This gives a few advantages of a secondary 



* See this Journal, iii. (1883) p. 302. 



