302 General Notes. [March, 
opment of the elater, so characteristic of the Collembola, indi- 
cating, as it seems to me, that that organ, in the genera in which 
it is absent or rudimentary, has been lost through degeneration ; 
and thirdly, because the egg is more decidedly meroblastic or 
teleplasmic than that of Isotoma.— Forn A. Ryder. 
\ 
PHYSIOLOGY: 
REPORT OF COMMITTEE ON DISINFECTANTS OF THE AMERICAN 
Pustic HEALTH Association.—A little more than a year ago the 
Public Health Association, stirred up by the prospective speedy 
advent of cholera in this country, took steps to arm both practition- 
ers of medicine and the public at large against not only that dis- 
ease but all ailments supposed to owe their existence to “ germs. 
A committee was appointed consisting of Drs, Sternberg and 
Smart, of the Army, Raymond, of Brooklyn, Vaughan, of Ann 
Arbor, Leeds, of New Jersey, Watkins, of New Orleans, ang 
_ Rohé, of Baltimore, to investigate the efficiency of the various | 
obtainable germicides and antiseptics in respect to sanitation and 
preventive medicine. Probably no more competent and conscien- 
tious workers than are some, if not all of the members of this 
fectants are antiseptics, but not all antiseptics are disinfectants. 
The work of the committee was limited to the study of the dis- 
infecting properties of the substances investigated. . 
e report consists partly of the descriptions of original experi- 
ments, and partly of historical essays, embodying the results of 
the most trustworthy investigators in this field. The general 
reader would search in vain the mass of bacteria literature to find 
some definite idea of the comparative value of different disinfec- 
tants ; but in the work before us the confusion is reduced to 4 
| Minimum, because the many different substances investigated are 
considered from the same standpoint and after the same methods. _ 
- It means very little when one experimenter declares that chromic 
acid, for example, is an antiseptic in the proportion 1 : 1000, and 
another that carbolic acid has the same power when of the stre 
I: 500; for the more concentrated the strength of the germ-food 
solution the greater must be the concentration of the antiseptic to 
=~ be efficient, and a percentage of antiseptic, that would prevent the 
_ / development of germs for the space of three days, might be liv 
_ down by bacteria in the course of six. | 
© — Mercuric chloride as a disinfectant easily stands at the head of 
substances readily obtainable. As this substance is a violent 
i : 1T his department is edited by Professor HENRY SEWALL, of Ann Arbor, Michigan- 
"X 
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