ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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morphological characters proper to their species, but were further distin- 
guished from one another by the typhoid not fermenting sugar, not 
coagulating milk, and giving no indol reaction, and by the coli cultures 
coagulating milk, fermenting sugar, and giving a positive indol reaction. 
The virulence of the cultures was found to be extremely high, 0*02 of a 
loopful of a 24 hours old agar culture of typhoid suspended in 1 ccm. of 
bouillon killing a guinea-pig in 13-20 hours, and 0*002 of a loopful of a 
coli culture being fatal in 10-12 hours. Expressed in weight these 
quantities would be equivalent to 0*000036 grm. and 0*0000036 grm. 
The principal conclusions arrived at by the authors are, that by treating 
dogs with increasing doses of virulent typhoid or coli bacteria, bodies 
are produced in the blood of these animals which possess a specific pro* 
tective power, but only against those bacteria to which they owe their 
origin. This seems to support the view that typhoid and coli bacteria are 
distinct species. Normal serum, i. e. serum of animals not so treated, 
also exerts a certain amount of protective power. Typhoid serum is 
more strongly protective against coli bacteria than normal serum, and 
coli serum is also stronger than normal serum against typhoid bacteria. 
One interesting result was that high and low doses were ineffective, 
while with medium doses the animals survived (Table vi.) For further 
particulars, the original should be consulted. 
Bacterium gelatinosum Betse.* — Dr. F. Glaser has isolated a bac- 
terium which exerts on beet-juice an action very similar to that of 
Leuconostoc mesenterioides. Pure cultivations were easily obtained on 
beet-juice gelatin, on which in about twenty-four hours white milky 
colonies developed, the gelatin being quickly liquefied. The bacteria 
were extremely mobile, and when stained with methylen-blue, were found 
to be short rodlets, several being often joined together. Cultivated in 
beet-juice the optimum temperature was 40°-45° ; and after about twelve 
hours’ growth in the medium the surface became covered with a jelly- 
like membrane. Similar but less marked growth appearances occurred 
in beer-wort. On neutral 10 per cent, molasses it did not grow, this 
defect serving as a distinguishing criterion between Bacterium gelatino- 
sum Betse and Leuconostoc for the latter grows with remarkable rapidity 
in that medium. If, however, the membrane from a beet-juice medium, 
after treatment with alcohol or after incineration, be added to the 
molasses, a membrane forms ; hence the inorganic bodies present in the 
membrane, such as phosphoric acid, iron oxide, and magnesia, must be 
necessary for the development of the bacterium. Another distinguishing 
feature between this bacterium and Leuconostoc is that the fermentation 
product of the former is alcohol, that of the latter lactic acid, when 
cultivated in beet juice. The fermented juice reduces Fehling’s solu- 
tion ; from which it may be inferred that the beet-sugar is inverted. 
The gelatinous membrane has characters similar to those of beet- 
gum ; it is soluble in warm dilute acids ; a hydrochloric acid solution 
reduces Fehling’s solution, the red suboxide being precipitated ; a sul- 
phuric acid solution gives a greenish-yellow precipitate ; it is easily 
soluble in caustic alkali, but insoluble in baryta water and in lactate of 
lime. 
* Centralbl. f. Bakteriol. u. Parasitenk., 2 te Abt., i. (1895) pp. 879-80. 
1896 R 
