5 TERILIZA TION AND DISINFECTION. 117

Kronig, as its boiling-point is i68°-i78° C., and thus
sufficiently high to kill spores. The use of cumol for the
sterilization of catgut has been carefully investigated by
Clarke and Miller.1

Ligatures of silk and silkworm-gut are boiled in
water immediately before using, or are steamed with the
dressings, or placed in test-tubes plugged with cotton and
steamed in the steam sterilizer.

At present, in most hospitals, instruments are boiled
before using in a 1-2 per cent, soda solution. Plain
water has the disadvantage of rusting the instruments,
and during the operation they are either kept in the boiled
water or in carbolic solution. Andrews makes special
mention of the fact that the instruments must be com-
pletely immersed to prevent rusting.

During the operation the wound is frequently washed
with normal salt solution, applied by sterile marine or
gauze sponges.

The water and the salt solution used for surgical pur-
poses are to be sterilized before using, either by steaming
for a prolonged period, or by the intermittent method.
Large hospitals are generally furnished with special appa-
ratus for supplying sterile distilled water in large quantity.

To La Place belongs the credit of observing that the
efficacy of bichlorid of mercury is greatly increased by
the addition of a small amount of acid, by which the
penetration is increased and the formation of insoluble
album mates lessened.

The knowledge that the action of germicides is chem-
ical, and that the destruction of the bacteria is due to the
combination of the germicide with the mycoprotein, is
apt to lessen our confidence in the permanence of their
action. Geppert has shown of bichlorid of mercury that
in the reaction between it and anthrax spores the vitality
of the latter seems lost, but that the precipitation of the
bichlorid from this combination by the action of ammo-
nium sulphid restores the vitality of the spore.

1 Bull, of the Johns Hopkins Hospital, Feb. and March, 1896.