CHAPTER X. 
THE DESTRUCTION OF BACTERIA BY THE CHEMICALS. 
Many chemical substances when brought in contact 
with bacteria unite with their cell substance. New 
compounds are thus formed, and the life of the bacteria 
and the disinfecting properties of the substances are usu- 
ally destroyed. While in the vegetative stage bacteria 
are much more easily killed than when in the spore 
form, and their life processes are inhibited by substances 
less deleterious than those required to destroy them. 
Bacteria both in the vegetative and in the spore 
form differ among themselves considerably in their 
resistance to the poisonous effects of chemicals. The 
reason for this is not as yet clear, but is apparently 
connected with the structure and chemical nature of 
their cell substance. 
Chemicals are more poisonous at fairly high than at 
a low temperature, and act more quickly upon bacteria 
when they are suspended in fluids singly than when in 
clumps. The increased energy of disinfectants at higher 
temperatures indicates in itself a probability that a true 
chemical reaction takes place. In estimating the ex- 
tent of the destructive action of chemicals the follow- 
ing degrees are usually distinguished: 
1. The growth is not permanently interfered with, 
but the pathogenic and zymogenic functions of the 
organism are diminished—atltenuation. 
2. The organisms are not able to multiply, but they 
are not destroyed by antiseptic action. 
