STERILIZATION AND DISINFECTION. 113

surgeon which cannot well be rendered incandescent,
exposed to dry heat at 150° C., steamed, or intermittently
heated without injury. For these objects disinfection
must be practised. Ever since Sir Joseph Lister intro-
duced antisepsis, or disinfection, into surgery there has
been a struggle for the supremacy of this or that highly-
recommended germicidal substance, with two results—
viz. that a great number of feeble germicides have been
discovered, and that belief in the efficacy of all germi-
cides has been somewhat shaken; hence the origin of the
successful aseptic surgery of the present day, which
strives to prevent the entrance of germs into, rather than
their destruction after admission to, the wound.

For a complete discussion of the subject of antiseptics
in relation to surgery the reader must be referred to the
large text-books of surgery, where much space is thus
occupied. A short list of useful germicides of which
the respective values are given, and a brief discussion
of some of the more important measures, can alone find
space in these pages. The antiseptic value of some of
the principal substances used may be expressed as fol-
lows, the figures indicating the strength of the solution
necessary to prevent the development of bacteria :

Pyoktanin (methyl violet) . i : 2,000,000—i : 5000.

Formalin.........i 125,000—i 15000.

Bichlorid of mercury . . . i: 14,300.

Hydrogen peroxid.....i : 20,000.

Formalin.........i : 20,000.

Nitrate of silver......1:12,500.

Creolin..........i: 5000 to i : 200 (does not kill

anthrax).

Chromic acid.......i: 5000.

Thymol..........i : 1340.

Salicylic acid.......i : 1000.

Potassium bichromate . . . i: 909.

Trikresol.........I : 1000—i : 500.

Zinc chlorid........i : 526.

Potassium permanganate . i : 285 ; not prompt in action.

Nitrate of lead......i : 277.

...........i : 200.