72 BACTERIA. 



to fluids, in which putrefa'ction and fermentation would 

 ordinarily take place, prevented the incidence of these 

 processes. He found at the same time that the fermen- 

 tations set up by chemical ferments, such as diastase and 

 synaptase, remained entirely unaffected by the action of 

 carbolic acid, and the result of his earlier experiments 

 led him to believe that the process of fermentation was 

 due to the action of living organized creatures which, like 

 the higher plants and animals, could be killed by the 

 carbolic acid. When they were allowed to develop freely 

 they brought about fermentation ; when their growth was 

 stopped, or they were killed, fermentation could not go on. 

 The same reasoning, he thought, might be applied to 

 infection and miasma, and he concluded that disease pro- 

 cesses were the result of fermentations or decompositions 

 going on within the tissues, and brought about by the 

 above or similar organisms. Pus formation was the result 

 of the action of germs falling from the surrounding air 

 into a wound. By the application of his germicidal re- 

 agents to wounds, vaccine vesicles, and suppurating 

 surfaces, he attempted to destroy these organisms out- 

 side the body whilst they were actually attacking the weak 

 points. 



This was really the first step in the direction of an anti- 

 septic treatment of wounds. Whilst treating by his method 

 wounds in the human subject and in the dog he saw " that 

 pus remained entirely absent, or was reduced to a minimum, 

 putrid alterations were absent," and the wound healed 

 rapidly. All these results were due, he maintained, to the 

 destruction of the microzoa or infusoria by his carbolic acid 

 lotions. The paramount importance of this theory was only 

 afterwards fully appreciated and worked" out by Lister, who 

 saw that, owing to the difficulty of killing germs after they 

 had once made their way into the tissues, it was absolutely 

 necessary that such organisms should be prevented from 

 gaining access to the wounds at all, and it is upon the 

 attainment of this end that his well-known antiseptic treat- 

 ment depends for its success. 



Accepting the truth of the statement that germs were the 

 cause of fermentation, Lister also came to the conclusion, 

 independently, that germs entering the wounds from outside 

 might be the cause of suppuration, and since germs were 



