Bacteria and Disease 7 



no organism may be designated as the specific cause 

 of any given disease unless it can be proved to be 

 invariably present in every case, and can be isolated 

 from the infectious materials. Henle's clear conception 

 of bacteria as agents of infection was evidently too far 

 advanced for his day. At any rate, his views failed to 

 gain general recognition for a long time. 



Pasteur's researches prepared the ground for such 

 recognition. A further step in advance was made by 

 Lemaire when he showed that carbolic acid, poisonous 

 to animals and capable of suspending putrefaction, 

 could also stop pus-formation in wounds. Lister carried 

 the work forward and developed his method of anti- 

 septic surgery, a method through which medical science 

 has achieved such splendid results. Lister's announce- 

 ment of 1868 stimulated inquiry and brought to light 

 important facts. 



The investigations of Klebs during the Franco-Prus- 

 sian War traced the entrance and the development of 

 bacteria in wounds and their passing into the circulatory 

 system. Klebs and other investigators also noted the 

 constant presence of bacteria in diphtheritic infections. 

 An apparent relation was likewise found between bacteria 

 and other infectious diseases. For all that, much was sur- 

 mise and speculation rather than certainty. The bac- 

 teriological methods for the isolation and identification 

 of bacteria had not yet been developed, and no direct 

 proof could be furnished for the facts observed. 



The study of bacteria. The systematic study of bac- 

 teria was furthered by the work of Schroter, published 

 in 1872. In his studies of pigment-producing bacteria, 



