THE STORY OF NINETEENTH-CENTURY SCIENCE 



of these bacteria which secure the oxygen which all or- 

 ganic life requires, not from the air, but by breaking up 

 unstable molecules in which oxygen is combined ; that 

 putrefaction, in short, has its foundation in the activities 

 of these so-called anaerobic bacteria. 



In a word, Pasteur showed that all the many familiar 

 processes of the decay of organic tissues are, in effect, 

 forms of fermentation, and would not take place at all 

 except for the presence of the living micro-organisms. 

 A piece of meat, for example, suspended in an atmos- 

 phere free from germs, will dry up gradually, without 

 the slightest sign of putrefaction, regardless of the tem- 

 perature or other conditions to which it may have been 

 subjected. 



There was nothing in these studies bearing directly 

 upon the question of animal diseases, yet before they 

 were finished they had stimulated progress in more than 

 one field of pathology. At the very outset they sufficed 

 to start afresh the inquiry as to the role played by mi- 

 cro-organisms in disease. In particular, they led the 

 French physician Devaine to return to some interrupted 

 studies which he had made ten years before, in reference 

 to the animal disease called anthrax, or splenic fever, a 

 disease that cost the farmers of Europe millions of 

 francs annually through loss of sheep and cattle. In 

 1850, Devaine had seen multitudes of bacteria in the 

 blood of animals who had died of anthrax, but he did 

 not at that time think of them as having a causal rela- 

 tion to the disease. Now, however, in 1863, stimulated 

 by Pasteur's new revelations regarding the power of 

 bacteria, he returned to the subject, and soon became 

 convinced, through experiments by means of inocula- 

 tion, that the microscopic organisms he had discovered 



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