SCHIEFFERDECKER S MICROTOME. 35 



about midway between the centre and the edge of the cornea, 

 wliich is the very part to which I wish to call attention in 

 this note. In a matrix, stained faintly yellowish-brown, Ave 

 find the lymph-canal system mapped out in an exceedingly 

 distinct manner, and in it the corneal corpuscles present 

 themselves as very conspicious structures. As is well known 

 (see Strieker's paper), they are arranged in the kitten in streaks 

 or groups in which the cells are separated or rather united 

 by linear interstitial substance — in silver preparations by a 

 dark line ; generally at the edge of these groups the corpu- 

 scles are provided with a few thick processes. At some places 

 the streaks are so broad that they contain three, four, or 

 even five corpuscles, arranged quite like an endothelium. 

 In the region under consideration, the substance of the 

 corneal- cor pusclts appears granular and of a beautiful purple- 

 broivn colour, whereas the nucleus is clear, and contains a 

 few dark granules, the outlines of the lyinp)h-canal system 

 containing these corpuscles being at the same time very well 

 defined. 



The beautifully tinted granular corpuscles, each with a 

 clear oval nucleus, separated by dark lines and contained 

 in the sharply outlined ' lymph-canal system, and all this 

 embedded in a perfectly transparent matrix faintly stained 

 yellowish- brown, is, I think, one of the prettiest and most 

 diagrammatic of histological objects. 



Schiefferdecker's Microtome. By P. Kidd, B.A. 



The following instrument is a modification of Smith's 

 microtome, devised by Dr. Schiefferdecker. It has the special 

 advantage that thin sections of large size can be made with- 

 out having recourse to embedding. 



The object which is to be cut is fixed by means of a 

 clamp (c) against the inner surface of the brass cylinder (a). 

 This clamp is worked by two screws {s s). 



The brass cylinder {a), which has a diameter of about one 

 inch and a quarter, is fixed, and a circular plate (b) moves 

 up or down on a by means of a screw. 



The circular plate is turned round through one or two 

 degrees after each section is made. An index (d) marks the 

 number of degrees through which the circular plate is 

 turned. The only precautions necessary in using the micro- 

 tome are— 



