ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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becomes impossible, or to the fatal toxaemia resulting from the absorp- 
tion of the metabolic products of the micro-organism. 
As an example of the first kind anthrax is cited, and of the latter 
cholera, typhus, diphtheria, tetanus. Thus the former class of patho- 
genic organism may be termed septic and the latter toxic, and while 
the septic organisms are combated either by immersing the organism 
or rapidly killing the bacteria, a toxemia can only be opposed by the 
encountering it with an antidote. 
The toxaemia may be neutralized in one of two ways, either by a 
direct antidote or by means of a preliminary treatment which shall 
render the animal unsusceptible (giftfest). 
The attention of the authors was chiefly devoted to obtaining a 
substance which should possess the property of neutralizing, or at least 
being inimical to bacterial poison. This was found in extracts of the 
thymus and lymphatic glands, and numerous examples are given of the 
efficacy of these substances against the poisons of cholera, tetanus, diph- 
theria, &c. Even the blood-serum of rabbits which had been rendered 
invulnerable by means of the thymus extract was found to confer similar 
immunity. 
But the interesting curiosity about the immunizing substance is that 
after 11 it is not contained in the thymus but is only developed therein 
after bacteria have been cultivated in a nutrient medium to which the 
thymus extract has been added. Eor no amount of the thymus extract 
of itself confers even modified immunity, consequently the immunizing 
substance must be a bacterial product ; and this is confirmed by the fact 
that there can be obtained from typhus cultivations a substance which 
will confer on mice invulnerability against very strong typhus in- 
toxication, The cells of toxic bacteria therefore produce at one and the 
same time a specific poison and a substance inimical to this poison. In 
the typhus bacilli it remains incorporated with the microbe itself, for 
only small quantities of the protective principles can be obtained after 
passing a cultivation through a Chamberland’s filter. 
Narcosis and Immunity.* — Prof. E. Klein and Dr. C. F. Cox well 
give the results of some experiments made by narcotizing frogs and rats 
with a mixture of equal parts of chloroform and ether, and inoculating 
them with anthrax. The narcosis was kept up for some minutes, and 
the injection was a pretty strong dose of virulent anthrax, the frogs 
receiving the virus in the dorsal lymph-sac, and the rats in the sub- 
cutaneous tissue of the groin. The object of these experiments was to 
see to what extent the natural immunity of these animals would be 
affected by these anaesthetics. 
In series i. frogs, in series ii. rats, were narcotized, and injected 
during narcosis. All died ; all the control animals remained alive. In 
series iii. the injections were made at various intervals before narcotiza- 
tion : one of these showed that anthrax spores were not destroyed in 
four hours. In series iv. the injections were made after narcosis ; it 
was found that one hour sufficed for the animals to recover from the 
effects of the narcosis. 
* Centralbl. f. Bakteriol. u. Parasitenk, xi. (1892) pp. 4G4-7. 
1892. 2 0 
