ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
325 
also a specific action, which is most powerful in the case of chlorine. 
Phenol acts better in 5 per cent, solution than at higher concentrations, 
and the effect is increased by the addition of metallic salts, especially 
sodium chloride ; it is diminished if mixed with alcohol, and is never as 
great as that of mercuric chloride. 
Plurality of Morbific Products from a single Pathogenic Microbe.* — 
M. A. Charrin contends for the plurality of morbific products from a 
single pathogenic microbe, asserting that the present notion which assigns 
the power of a micro-organism over the animal body to a single product, 
a toxin, is insufficient to explain the phenomena. The contention is 
supported from experiments made with cultures of B. pyocyaneus. The 
substances precipitated by alcohol induce emaciation, enteritis, and fever, 
and also act as excito-motors of the spinal cord. The substances which are 
soluble in alcohol principally affect the heart ; while the volatile aromatic 
principles act as constrictors on the capillaries. 
Besides the foregoing, there is some evidence of the presence of a 
ferment which is capable of decomposing asparagin. The fact that the 
B. pyocyanens consumes much oxygen which is necessarily drawn from 
our tissues, and that it elaborates ammoniacal compounds and traces of 
methylamin, points in the same direction. The part played by the blue 
or green pigment, though inconsiderable, cannot be overlooked. From 
the foregoing considerations, and while admitting that there is a principal 
toxin, usually albuminoid, more important than the rest, it is none the less 
true that other morbific agents are called into existence by a single 
microbe. Such data afford an easy explanation of the multiplicity, the 
variety, and the occasional predominance of certain symptoms. 
Microbic Agents of Cheese-Ripening.f — Experiments made by M. 
E. de Freudenreich relative to the maturation of cheese tend to show 
that the lactic ferments are endowed with the power of attacking casein 
and of transforming it into soluble albuminoid substances and amides. 
Taking into consideration the enormous increase in the number of lactic 
ferments in cheese during the process of maturation, it becomes evident 
that this variety of bacteria plays the most important part in the ripen- 
ing of cheese, at any rate of hard cheese. In soft cheese, Oidium lactis 
and yeasts are equally active. It is further pointed out that in ripening 
cheese the lactic acid ferments are quite different from those in sponta- 
neously coagulated milk ; hence it would seem possible that there exists 
a special class of ferments which, in virtue of their less intense lactic 
acid formation, are specially adapted for decomposing casein. 
Bacteria and the Decomposition of Rocks, f — Mr. J. C. Branner dis- 
cusses the question whether bacteria are important agents of rock decay, 
a notion promulgated by Muntz in 1890. This writer stated that the 
nitrifying organism was always present in decomposed rocks ; and this 
view was generally accepted. From a review of numerous observations 
made by competent persons, the author is of opinion that it is quite 
improbable that bacteria are responsible for any considerable part of the 
* Comptes Rendus, cxxiv. (1897) pp. 1047-9. 
t Ann. de Micrographie, ix. (1897) pp. 185-93; and Centralbl. Bakt. u. Par., 
2 te Abt., iii. (1897) pp. 23L-5. Cf. this Journal, 1896, p. 224. 
X Amer. Journ. Sci., iii. (1897) pp. 438-42. 
1897 
z 
