28 ANTISEPTIC TREATMENT OF WOUNDS. 
all micro organisms is moisture; rapid drying as welf as nat- 
ural lack of moisture are not favorable conditions for the 
growth and life of those small vegetable organisms. There- 
fore, all means, which energetically withdraw moisture, cause a 
condition which hinders their growth and action. Hand in 
hand with this withdrawal of moisture, a change in the tissues 
on which these microbes have settled, usually takes place, for 
instance, in wounds where by the use of strongly drying reme- 
dies a coagulation of the albumen takes place so much 
that a fit nutritive medium no longer exists. The rem- 
edies we use for the purpose of disinfection are so hetero- 
geneous that we need not wonder at this, especially if we 
consider. the different ways by which we attain the desired 
effects through disinfection. In view of the above mentioned 
theories, however, their action cannot be said to be so ex- 
clusive that one remedy will kill the microbes only, while an- 
other will only deprive them of the possibilities of existence by 
changing their nutritive medium, or that a third will only re- 
move them from the infected medium. Most disinfectants act 
simultaneously in two or more ways, so that classification ac- 
cording to their own action is impossible. As to nature, how- 
ever, they may be classified into: _ 
First—Physical disinfection agents. 
Second—Chemical disinfection agents. 
Among the physical agents we class all those surgical in- 
struments with whose aid we can remove infected material in a 
purely mechanical way, for instance, the knife, scissors, sharp 
scoop, etc., also the high degrees of heat in the form of the fir- 
ing iron or thermo-cautery of Paquelin, and finally the with- 
drawal of moisture, namely, exsiccation and permanent irriga- 
tion. The action of these remedies has been mostly discussed 
above; we will therefore not go into further details here, nor as 
to their uses; an opportunity in future chapters for that will 
be found. 
We will now discuss those chemical agents which are hostile 
to the development of micro organisms. 
The rotation in which they are taken up depends on their 
