114 PA THOGENIC BA CTERIA.

Boracic acid........i: 143.

Chloral hydrate......i: 107.

Ferrous sulphate ...... i: 90—1 :200, Sternberg.

Calcium chlorid . . . . . i: 25.

Creosote.........i: 20.

Carbolic acid.......i: 20 :: i : 50.

Alcohol..........i: 10.

Ether. Pure ether will not kill anthrax spores immersed
in it for eight days.

The value of .antiseptics, like that of disinfectants, is
always relative, the destructive as well as the inhibitory
power of the solution varying with the micro-organism
upon which it acts. The following table, from Boer,

will illustrate this:

Methyl Violet (Pyoktanin).

Restrains. Kills.

Anthrax bacillus......i: 70,000 i : 5000

Diphtheria.........i: 10,000 i : 2000

Glanders...... . i: 2500 i: 150

Typhoid..........i: 2500 i: 150

Cholera spirillum.....i: 30,000 i : 1000

"Large numbers of both strongly and feebly antiseptic
.-substances have purposely been omitted from the above
lists, compiled from Sternberg and Micquel, as either in-
appropriate for ordinary use or as having been replaced
by better agents.

The newest, and one of the best germicides for all pur-
poses is formaldehyde. Its use as a vapor for the sterili-
zation of infected rooms was first suggested by Trillat in
1895, but it did not make much stir in the medical world
until a year or more had passed and a 40 per cent, solu-
tion of the gas, under the name of "Formalin," had
been placed upon the market. The original method con-
sisted of the evolution of the gas from methyl alcohol by
volatilizing it in a steam apparatus, and passing the vapor
over a heated metal plate. At present the original auto-
clave has been replaced by the apparatus shown in Fig.
19, in which a solution of formochloral is volatilized by
heating under a pressure of three atmospheres.