ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
409 
M. Petermann, who has followed quite implicitly the procedure given 
by Ogata* for obtaining an immunity-giving substance from rat’s blood, 
has failed to corroborate the statements of the Japanese professor, all 
his numerous experiments having quite failed. 
Vaccinating Products of Liquid Cultures of Tubercle Bacilli.t— 
In order to determine whether the soluble products of the tubercle 
bacillus favour or prevent the development of this micro-organism in 
the animal body, MM. J. Courmont and L. Dor made some experiments 
on rabbits by first injecting these animals (intraperitoneal and intra- 
venous) with considerable quantities of tubercle cultures freed by 
filtration from bacilli, and then either simultaneously or at different 
intervals of time injecting into their veins virulent cultivations. For 
three days after the inoculation the weight of the animals diminished, 
but afterwards continuously ascended until they eventually ‘weighed 
500-1000 grm. more than before the inoculation. The control animals 
which had not received the culture-filtrate died of chronic tubercular 
arthritis. Of four rabbits which received a filtered and afterwards a 
virulent injection, two resisted the infection and retained this resistance 
seven months afterwards. 
The authors conclude from the results of their experiments that the 
soluble secretion products of the tubercle bacilli in doses of 1 ccm. per 
cent, of the animal’s weight do not exert any toxic action on rabbits, 
whether the injections have been made into the peritoneum or into the 
veins, and further that they possess the power of protecting tbe organism 
against the after infection of the very microbe which produced them. 
Tolerance to Microbic Products.^ — MM. Metschnikoff and Roudenko, 
by means of forced injections of sterilized Pyocyaneus cultivations into 
rabbits, have succeeded in half the number of cases in producing 
certain tolerance to the virus of Pyocyaneus, a result opposed 
to that of Charrin and Gamaleia, whose animals were rendered more 
resistant than normal. Analogous results were obtained with Vibrio 
Metschnikovi for guinea-pigs, although the experiments were at first 
in consonance with those of Gamaleia, the vaccinated guinea-pigs being 
just as sensitive to fatal doses of the sterile poison as normal animals. 
These diversities appeared to depend chiefly on individual differences in 
the animals experimented on. As Gamaleia had noted in 1889, the 
authors found that tubercular disease exercised great influence on the 
sensitiveness of the animals to the bacterial poison ; for while in healthy 
guinea-pigs the reaction period for small or moderate doses of sterilized 
cultures of V. Metschnikovi was of short duration, the tuberculous 
guinea-pigs succumbed with considerable hyperasmia of the tuberculous 
foci. 
The authors conclude from their experiments that tolerance to 
toxines may be possible, but this in no way shows that the existence of 
protective inoculation depends on this tolerance, since vaccinated 
* Annal. de l’lnst. Pasteur, 1891, p. 506. Cf. this Journal, 1891, p. 797. 
t La Province Me'd., 1890, p. 591. See Centralbl. f. Bakteriol. u. Parasitenk. 
xi. (1892) p. 114. 
t Annal. de l’In6t. Pasteur, 1891, p. 567. See Centralbl. f. Bakteriol. u. Para- 
sitenk., xi. (1892) pp. 56-7. 
