ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 
799 
In less quantity a sediment consisting of well-stained cocci is 
deposited at the bottom of the cultivation medium (bouillon). 
Dried on silk threads the micro-organisms were killed by a 1 per 
cent, solution of violet pyoctanin in from 75-90 minutes. 
Yellow pyoctanin took much longer. From these and other experi- 
ments the author concludes that anilin pigments included under the 
designation of pyoctanin possess feeble antiseptic properties, but that 
they are under certain circumstances more effective, from their pene- 
trative power, than sublimate. 
Disinfecting property of Peroxide of Hydrogen.*— Herr Altehoe'fer 
recommends peroxide of hydrogen as a very suitable and effective means 
for disinfecting potable water from pathogenic germs. For completely 
destroying the non-pathogenic and pathogenic organisms found in water, 
the experiments of the author show that the relative concentration should 
be 1 to 1000, and the influence of the germicide should be allowed to 
be exerted for 24 hours. 
The concentration proposed by the author is not only effective and 
quite harmless, but is extremely economical. 
Attenuation of Bacillus of Tetanus.f — Dr. G. Tizzoni and Dr. G. 
Cattani describe the alterations in pathogenic power and biological 
characters which the bacillus of tetanus undergoes after being dried 
on silk threads, and when cultivated on different nutrient media, and 
when subjected to diverse environments. 
The main characteristics of cultivations of virulent tetanus are that 
they always liquefy gelatin, always show a decidedly alkaline reaction, 
emit a very ill odour, and when inoculated in animals, even in small 
quantity, kill them in 24-36 hours with the well-known symptoms 
of experimental tetanus. But when much attenuated, these cultivations 
no longer liquefy gelatin even when left in the thermostat for quite a 
long time ; they do not emit any odour and present a markedly acid 
reaction. 
Such are the main differences between virulent and attenuated 
cultivations. Numerous other slight differences are described but they 
are less important than those mentioned. It may be added that the 
authors believe that the acidity of the attenuated cultivation is a con- 
sequence of this condition rather than the cause of the attenuation. 
Action of the Constant Current on Pathogenic Micro-organisms. £ — 
M. K. Yerhoogen divides his remarks on the action of the constant 
current on pathogenic microbes into two categories according as the 
object is electroly sable or not. If the former, then the action of the 
current is chemical ; if the latter, this action is simply physical. 
The treatment of tumours is considered under the section dealing 
with the chemical action of the current, and herein the statement is 
made that the positive pole should be chosen when electrolytic dispersion 
of a tumour is desired. 
In the section discussing the physical action of the electric current, 
* Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 129-37. See Bot. Cen- 
tralbl., xlv. (1891) p. 251. 
f Atti K. Accad. dei Lincei, vii. (1891) pp. 249-57. 
j Bull. Soc. Beige Micr., xvii. (1891) pp. 168-91. 
