6 BIOLOGY AND TECHNIQUE 



Meanwhile, Pasteur, parallel with his researches upon spontaneous 

 generation, had been carrying on experimeilts upon the subject of 

 fermentation along the lines suggested by Cagniard-Latour. As a 

 consequence of these experiments, he not only confirmed the opinions 

 both of this author and of Schwann concerning the fermentation of beer 

 and wine by yeasts, but was able to show that a number of other fer- 

 mentations, such as those of lactic and butyric acid, as well as the de- 

 composition of organic matter by putrefaction, were directly due to the 

 action of microorganisms. It was the discoverj^ of the living agents 

 underlying putrefaction, especially, which exerted the most active 

 influence upon the medical research of the day. This is illustrated by 

 Lister's work. The suppurative processes occurring in infected woimds 

 had long been regarded as a species of putrefaction, and Lord Lister, 

 working directly upon the premises supplied by Pasteur, introduced 

 into both the active and prophylactic treatment of surgical wounds, 

 the antiseptic principles which alone have made modern surger}' possible. 



There now followed a period in which bacteriological investigation 

 was concentrated upon problems of etiology. Stimulated by Pasteur's 

 successes, the long-cherished hope of finding some specific microorgan- 

 ism as the causal agent in each infectious disease was revived. 



PoUender, in 1855, had reported the presence of rod-shaped bodies 

 in the blood and spleen of animals dead of anthrax. Brauell, several 

 years later, had made similar observations and had expressed definite 

 opinions as to the causative relationship of these rods to the disease. 

 Convincing proof, however, had not been brought by either of these 

 observers. Finally, in 1863, Davaine, in a series of brilliant investi- 

 gations, not only confirmed the observations of the two authors men- 

 tioned above, but succeeded in demonstrating that the disease could 

 be transmitted by means of blood containing these rods and could never 

 be transmitted by blood from which these rods were absent. Anthrax, 

 thus, is the first disease in which definite proof of bacterial causation 

 was brought. 



Speaking before the French Academy of Medicine at this time, 

 Davaine suggested that the manifestations of the disease might in 

 reality represent the results of a specific fermentation produced by the 

 bacilli he had found. This, in a crude way, expresses the modern 

 conception of infectious disease. 



Within a few years after this, 1868, the adherents of the parasitic 

 theory of infectious diseases were further encouraged by the discovery, 

 by Obermeier, of a spirillum in the blood of patients suffering from 



