ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



520 



screw s. The knife is a carpenter's plane-iron, and this is fitted into 

 the carrier a, which serves also for the purpose of sharpening on the 

 hones. Two plates, p y, about ^ in. thick, are fastened to the bop in 

 order to prevent the edge of the knife from coming in contact with the 

 microtome. A small piece of tin t bent at right angles is so fastened 

 that when its edge comes in contact with the milled head of the micro- 

 meter screw s it makes a clicking. The microtome works equally well 

 with cold brine, carbon dioxide, ether, or rhizolene. 



A sectional view of the attachment, which serves both as knife-carrier 

 and handle for sharpening, is seen in fig. 120. It is made of brass or 

 copper. The knife k is firmly held in place by means of the screw s, 



UUf 



Fig. 120. 



which passes through a collar c soldered to the top plate p, which in turn 

 is fastened to the main body of the attachment by the screws m m. A 

 cylindrical piece of brass r serves as a roller and turns on the screws w to 

 as bearings. When the knife is placed for the first time on the hone 

 the carrier is so adjusted by means of the screw that the ground surface 

 lies flat on the hone. This position should be marked, so that when 

 re-sharpening is required the same position may be readily attained. 

 When placed in the microtome for cutting it is put J to \ in. further 

 back, so that its position is more vertical than when being sharpened. 



(4) Staining- and Injecting-. 



Staining the Tubercle Bacillus with Eosin.* — A. Mendoza states 

 that the bacilli of tubercle, leprosy, smegma, and others can be stained by 

 means of eosin. The preparations are treated for 24 hours in the cold, 

 or heated for about 15 minutes. The fuchsin is made up with carbolic 

 acid or an aldehyde of the aromatic series, to the action of which the 

 author ascribes the penetrability of the staining solutions. When stained 

 the preparations are decolorised with 10 p.c. acid alcohol. 



Staining the Spirochsetae of Syphilis.! — E. J. McWccney finds 

 the spirochetal of syphilis are negative to Gram, and that the results 



* Bol. Inst. Alfonso xiii., 1 (1905) pp. 9-11. 



t Brit. Med. Journ. (1905) i. pp. 1262-4 (1 fig.). 



Aug. 16th, 1905 2 n 



