236 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Yet with a few bacteria more certainty can be attained ; cholera vibrios 
and tubercle bacilli possess specific characteristics by which they can be 
easily identified. But even in the case of tubercle bacilli a caution is 
necessary, for the author notes that the bacillus of fowl tuberculosis 
is obviously a distinct though closely allied species. 
The next point discussed is the relation of bacteria to disease. The 
proof of a direct relation is perfectly clear with regard to a certain 
number of infectious diseases — anthrax, tuberculosis, erysipelas, &c. 
And as to some others, such as typhoid, cholera, diphtheria, relapsing 
fever, leprosy, there is little doubt, although the attempts at artificial 
infection have hitherto failed. 
After alluding to the importance of the metabolic products of bacteria 
and the recently discovered toxalbumins, the author expresses his opinion 
that the question of immunity can only be answered by the aid of bac- 
teriology, and then passes on to consider some of the biological phe- 
nomena of bacteria. 
After this the numerous failures of bacteriology are touched on, as in 
measles, scarlet fever, typhus, small-pox, rabies, influenza, and numerous 
other infectious disorders. 
The address concludes with a consideration of the methods at our 
disposal for combating pathogenic micro-organisms, either directly, as 
by disinfection, or indirectly, by the application of certain substances to 
the body which might render the bacteria inert, without injury to the 
organism. 
Germicidal Action of Blood-serum.* — For ascertaining the action 
of the blood-serum of sick or vaccinated animals, MM. Charrin and 
Roger passed carotid blood of the rabbit into iced sterilized vessels, and 
inoculated the serum obtained after coagulation with B. pyocyaneus. 
This microbe has, according to Buchner, a marked resistance to the 
germicidal action of blood-serum. From comparative experiments 
between the serum of normal animals and those which 24 hours 
previously had received an intravenous injection of B. pyocyaneus , 
and which were moribund, when the blood was withdrawn it was found 
that the serum of the latter was more resistant. After 24 hours the 
tubes were no more cloudy than previously, and microscopically only a 
few isolated bacilli were found, while the normal serum had become 
turbid and contained numerous bacilli. 
A resistance of intermediate intensity was shown by the serum of 
rabbits which had been repeatedly infected by the subcutaneous injection 
of B. pyocyaneus. Plate cultivations of the three kinds of serum 
showed great differences in the number of germs they contained. 
The germicidal action, accordingly, is intensified in the serum of sick 
and vaccinated animals. The authors consider, however, that immunity 
is the result of manifold conditions, and do not intend to throw any 
doubt on phagocytosis. 
The same authors f have recently extended their researches on the 
germicidal action of blood-serum to the bacillus of symptomatic anthrax 
* Comptes Kendus, cix. (1889) pp. 710-3. See Centralbl. f. Bakteriol. u. Para- 
eitenk., viii. (1890) pp. 283-4. 
f CR. Soc. Biol., 1890, No. 14. See Centralbl. f. Bakteriol. u. Parasitenk., viii. 
(1890) p. 283. 
