ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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1-1^ weeks, the pieces are transferred to a weak aqueous solution of 
nitrate of silver, and then for 48 hours or longer to a 1 per cent, solution 
thereof. 
This modification of Golgi’s method gave good results also with 
human cerebella or cerebra which had been kept for 2-3 days in a cool 
place. 
Preparation of Diphtheritic Toxin without Meat.*— Prof. Spronck, 
having found that yeast favoured the production of the diphtheritic 
toxin, now prepares the toxin by the following method. Ordinary 
yeast, not brewer’s yeast, is used. One kilo, is boiled in 5 litres of 
water for 20 minutes, the yeast being constantly stirred with a spatula. 
The decoction is poured out and allowed to stand 24 hours. To the 
supernatant fluid are then added 5 grm. of salt and 20 grm. of pepton. 
The fluid, which is slightly acid, is neutralised with soda, 7 ccm. of 
normal soda solution being added to the litre. It is then hot-filtered 
through paper, distributed into vessels, and steiilised at 120°. Thus 
prepared, the diphtheritic toxin is twenty times stronger than that pre- 
pared from old meat. 
(3) Cutting-, including: Imbedding- and Microtomes. 
New Microtome.f— M. P. Francotte describes a microtome made 
by^Jung which has the following advantages (fig. 119). It is of 
* Ann. Inst. Pasteur, xii. (1898) pp. 701-4. 
f Bull. Soc. Beige de Microscopie, xxiv. (1897-98) pp. 18-21 (1 fig.). 
