ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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small percentage of alkali to fluids which contain proteids, such as white 
of egg and the serum of blood. The fluid is then heated to the boiling 
point or over it in the autoclave. By this means it is converted into a 
clear transparent jelly. It is then a medium suitable for the growth of 
a large variety of germs. 
Preparation and Properties of Tetanus Antitoxin.* — Dr. R. T. 
Hewlett prepares tetanus antitoxin by cultivating the bacillus in yeast 
flasks in an atmosphere of hydrogen, the medium used being grape-sugar 
bouillon. After incubating at 37° for three to four weeks the cultures 
to which carbolic acid is added in the proportion of 0*5 per cent., are 
filtered through a Chamberland bougie. One-hundredth of a ccm. of the 
toxin thus obtained will kill a guinea-pig weighing 300-400 grm. 
The toxin is next weakened by adding an equal volume of Gram’s 
iodine solution, and this mixture is injected subcutaneously into a horse, 
starting with * 5 ccm. and going up 22 ccm. After this intravascular injec- 
tions were made; these ranged from 4-70 ccm. and were continued for 
about 5 weeks, when a period of a month without injections was allowed 
to elapse. At the end of this time the antitoxic power of the serum was 
found to be about 50,000. After this the treatment was rapidly pushed 
until the antitoxic power was equal to 1,000,000. 
The antitoxic serum was obtained by bleeding from the jugular vein 
into sterilized vessels, and after 24 hours pipetting off the clear serum 
used for injection. To obtain the substance dry, it must be evaporated 
in vacuo over sulphuric acid. According to the author the experimental 
effects of the antitoxin smack of the marvellous ; thus 0 * 0005 ccm. will 
protect a 400-500 grm. guinea-pig from 0 • 01 ccm. of the toxin, and a 
mixture of the two in the proportion of 50 to 1 is quite inert. 
Alkali Albuminates in the Preparation of Cultivation Media, j — 
Dr. G. Deycke J prepares agar for isolating diphtheria bacilli in the 
following way: — 1 per cent, alkali albuminate, 1 per cent, pepton, 
1/2 per cent, salt, 2 per cent, agar, and 5 per cent, glycerin are mixed 
with the adequate quantity of distilled water. This mixture is first 
neutralized with pure hydrochloric acid and next alkalinized with 1 per 
cent, of a soda solution consisting of 1 part soda and 2 parts water. 
After standing for several hours at room temperature, the mixture is 
boiled in a sterilizer for 3/4—1 hour. The hot agar is then filtered 
through a thin layer of cotton-wool into test-tubes, and then steam- 
sterilized for 1/2 hour, after which it is allowed to set in oblique position. 
Prepared in this way the agar is a little cloudy, but the procedure has 
the advantage of rapidity. 
For cultivating cholera bacilli a nutrient gelatin is made thus : — 
2^ per cent, alkali albuminate, 1 per cent, pepton, 1 per cent, salt, and 
10 per cent, gelatin are mixed with the proper proportion of distilled 
water and then neutralized with 2 per cent, of the before-mentioned soda 
solution. After this it is boiled for 1 J-2 hours in a steamer, and finally 
filtered in a hot- water funnel through blotting paper into test-tubes, which 
are boiled for 10 minutes on three consecutive days. 
* Brit. Med. Journ., March 2, 1895, pp. 464-5. 
f Centralbl. f. Bakteriol. u. Parasitenk., 1© Abt., xvii. (1895) pp. 241-5. 
X See also this Journal, 1894, p. 750. 
R 2 
