700 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
animals may be used as an injection material. Besides being equally 
effective there is a much larger yield of the fluid, often over 65 per cent, 
of the blood volume. Antitoxin plasma can always be obtained perfectly 
free from red corpuscles. It is readily prepared by leading off the blood 
from the horse’s vein into a little citrate of soda dissolved in normal salt 
solution. An addition of 5 grm. of citrate of soda for every 1000 
ccm. of blood is all that is required, provided that the tube through 
which the blood is led into the receiving vessel reaches quite down to 
the bottom of that vessel, so as to ensure a complete mixture. The 
easiest method of siphoning off the antitoxic plasma is to use a glass 
tube bent into a U-shape in such a manner as to leave one limb con- 
siderably longer than the other. Near the extremity of the longer limb 
another glass tube is to be fused on at an acute angle. To this side 
tube a piece of rubber tubing is to be attached. The other end of the 
rubber tube is fitted with a mouth-piece plugged with cotton- wool. A 
siphon is thus formed which can be started by exhausting the air in the 
side tube. A tap or a piece of rubber tube fitted with a pinchcock is 
fixed at the end of the long limb of the siphon. 
Importance of Sugar in Cultivating Media.* — Dr. Th. Smith, after 
pointing out that the presence of sugar in cultivation media is often of 
great importance, inasmuch as a differential diagnosis between two or 
more species may not be possible if sugar be absent, discusses the rela- 
tions between sugar, acid-formation, gas-formation, and anaerobiosis. In 
these connections the most important particulars are that with ordinary 
meat-broth, the formation of acid and gas are only noticed when sugar is 
present. The formation of acid keeps pace with the splitting up of the 
sugar and is common to all anaerobes (potential and essential). The forma- 
tion of alkali requires the presence of oxygen. Hence both in aerobiosis 
and. in anaerobiosis the one process may mask the other. All gas-forming 
species produce an explosive gas as well as C0 2 . If at least three kinds 
of sugar (including muscle sugar) be used, the formation of acid and 
gas are valuable diagnostic criteria. The division into acid and alkali 
formers must be given up. 
Preparing Clear Agar.j — Herr L. Zupnik recommends the follow- 
ing modification of Fraenkel’s sedimentation method for obtaining clear 
agar. Fluid agar is poured into a tall glass vessel placed in a steamer 
on a water-bath. The fire is gradually let out, and the whole apparatus 
left till the morning. IS ext day the solid mass of agar is easily removed, 
and the turbid portion cut away with a knife. 
Another procedure worth mentioning on account of its facility and 
simplicity consists in adding the requisite quantity of agar powder to 
perfectly clear meat-bouillon. The liquid is next steamed for an hour, 
and then filtered in a hot-water funnel through a thin layer of hydro- 
philous cotton-wool. The cotton-wool is adapted to the shape of the 
funnel, and then moistened with hot distilled water, any excess of water 
being pressed out with the finger. The hot agar is at once poured in, 
and it runs out in a full stream perfectly clear. 
* Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., xviii. (1895) pp. 1-9. 
t Tom. cit., p. 202. 
