STERILIZATION AND DISINFECTION. 115

.The gas is very penetrating, easily diffusing itself, and
is said to have enormous bactericidal powers. In experi-
ments conducted by Prof.
Robinson, of Bowdoin Col-
lege, the gas penetrated mat-
tresses and killed cultures in
tubes wrapped up in them.

There seems to be little
doubt of the abilitv of the

FIG. 18.—The Trillat autoclave.

FlG. 19.—Sanitary formaldehyde*re-
generator.

formaldehyde gas to disinfect, but there are few apparatus
upon the market at present that seem capable of discharg-
ing a sufficient volume of the gas with sufficient rapidity
to do the work. The physician, therefore, who desires
to disinfect with confidence should choose an apparatus
that has been shown by competent experiments to fill the
requirements.

The " formalin,n or 40 per cent, solution of the gas,
when fresh and tightly corked, is fatal to most bacteria in
dilutions of from i: 5000 to i: 25,000. It can be employed
with great advantage to spray the walls and floors of
rooms. It cannot be employed upon the skin or mucous
membranes, because of its marked irritating effect

The disinfection of the skin, both the hands of the
surgeon and the part about to be incised, is a matter of
importance. It is almost impossible to secure absolute
sterility of the hands, so deeply do the skin-cocci pene-
trate between the layers of the scarf-skin. The method at