ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
G99 
by means of a narrow pipe. The level of the water above the highest 
part of the vaulted bottom is never more than 1 cm., and it is owing 
to this that steam is rapidly and copiously developed. Through the 
space between the two cylinders circulates hot air, which, if desired, 
can be let out through an aperture in the lid. The excess of steam 
passes out through a pipe in the side and condenses in the receiver. 
Potato Media for Cultivating the Tubercle Bacillus.* — Herr Ws. 
Lubiuski prepares nutrient media containing potato for cultivating the 
tubercle bacillus in the following way. Four varieties were used : — 
(1) 4 per cent, glycerinised potato-broth ; (2) 4 per cent, glycerinised 
potato-agar ; (3) 4 per cent, glycerinised potato-meat-pepton-bouillon ; 
(4) 4 per cent, glycerinised potato-meat-pepton-agar. I kg. of clean, 
finely-chopped potato is boiled in 1500 com. of water for 3-4 hours on 
the open fire or in a steamer, and then the acid decoction filtered off. 
The filtrate, mixed with 4 per cent, glycerin and neutralised, is medium 
No. 1. By the addition of 1-1-5 per cent, agar to the latter, boiling and 
filtering, medium No. 2 is obtained. Media Nos. 3 and 4 are made 
like the ordinary meat-pepton media, except that instead of water the 
potato decoction is used, that is to say, 500 grin, of finely chopped up 
meat and 1000 ccm. of the potato-broth are, after standing for 24 hours, 
filtered and mixed with 1 per cent, pepton and ^ per cent. NaCl ; after 
boiling and so on, 4 per cent, glycerin is added. 
These media are also used with an acid reaction by merely omitting 
the neutralising alkali. 
Diphtheria Antitoxin as Culture Medium for the Diphtheria Ba- 
cillus.f — Profs. A. E. Wright and D. Semple point out the difficulty 
which the ordinary practitioner has in making a bacteriological diagnosis 
of diphtheria. This is due to the fact that blood serum, which consti- 
tutes by far the best culture medium for the diphtheria bacillus, is not 
readily obtained. This difficulty can be easily overcome by the use of 
the antitoxic serum, which is as good a culture medium for diphtheria as 
the serum which is derived from a non-immunised animal. A small 
quantityof the antitoxin should be poured into any clean, small wide- 
mouthed bottle. This bottle should be brought into the horizontal 
position, and the albuminous substances of the serum so coagulated as 
to adhere to the sides of the bottle. This may be conveniently done by 
laying the bottle sideways over the mouth of a steaming kettle. Any 
water of condensation having been poured off, the culture medium is to 
be allowed to cool down. It is then to be inoculated by passing a stout 
wire or glass rod, which has been brought in contact with the diphtheritic 
throat, lightly over its surface. The bottle is to be kept as nearly as 
possible at a blood temperature, and the microscopical examination may 
be undertaken after 24 hours. The material for examination may be 
obtained by lightly scraping the surface of the culture medium with a 
platinum needle. 
Diphtheria Antitoxic Plasma.J — Prof. A. E. Wright and Surgeon- 
major D. Semple state that the plasma instead of the serum of immunised 
* Centralbl. f. Bakteriol. u. Parasitenk., l tc Abt., xviii. (1895) p. 126. 
f Brit. Mecl. Journ., 1895, No. 1815, p. 907. X Tom. cit., p. 997. 
