ASEPSIS AND ANTISEPSIS. 
631 
purest air, if not renewed with sufficient frequency, becomes 
speedily contaminated by the exhalations and effete material 
from the animals of those breathing it. This, which is true in 
health, is still more quickly accomplished when the animal is 
diseased. It becomes, therefore, more important for the well¬ 
doing- of the sick animal than for the welfare of the well that 
an unlimited supply of pure air should be provided. When to 
the natural sources of air contamination there are added the 
emanations of suppurating wounds, the need of constant change 
in the surrounding air is more emphatic still, if its purity is to 
be preserved. While air is the great oxygen carrier for the 
needs of the living body, it receives in exchange from the body 
the debris of its disintegration. It is the vehicle of transporta¬ 
tion of an infinite variety of floating matter, the great mass of 
which is organic in character. Putrescible organic matter can¬ 
not long be exposed to the air without becoming the recipient 
of putrefactive germs from it. Aseptic wounded surfaces 
quickly become septic when exposed by reason of the floating 
septic particles that are conveyed. The best stimulant to the 
vital resisting power of a living tissue, by which the effects of 
sepsis are antagonized and overcome, is perfectly oxygenized 
blood. The air thus carries both the bane and antidote. The 
practical end, therefore, to be aimed at, in any given air-supply, 
is that there shall be as small a proportion of the bane and as 
large a proportion of the antidote as possible. This involves 
the removal, the suppression, or the diffusion, as much as pos¬ 
sible, of all sources of contamination, and the dilution of that 
which is unavoidable by the introduction of the largest quan¬ 
tity practicable of the purest air attainable. The purity and 
the sufficiency of the air are thus seen to have a double relation 
to the healing of wounds, one in a general relation, which the 
air shares with other hygienic conditions, and the other a 
special relation as a carrier of and an antidote to sepsis. 1 he 
hygienic conditions in the wounded animal must be made as 
good as possible before the whole duty of the surgeon is accom¬ 
plished. 
