552 Sir William Maceiveii [June 7, 



article of manufacture iu that town. He l^ecame thoroughly con- 

 vinced of the correctness of the observations and deductions 

 previously made hy Schwann and by Cagniard-Latour. He verified 

 and extended those ol)servations showing that fermentation was due 

 to micro-organisms, and coniirmed the observations of Schwann that 

 pure air had no effect in producing putrefaction. 



Pasteur demonstrated these facts by many diverse and original 

 experiments on fermental)le and putrescible substances. He showed 

 (1) that sterilized grape-juice did not ferment in the presence of 

 pure air, however long it might be kept, and that while thus exposed 

 none of the ferments of wine were produced in it ; (2) that blood 

 could be kept indefinitely exposed to pure air without undergoing 

 putrefaction — it yielded neither bacteria nor vibrios. 



An Organism found to be the Cause of a Disease -by 

 Davaine, 1850. 



In 1858 Pasteur had demonstrated that the whole process of 

 fermentation disproved the theory of spontaneous generation. He 

 showed that putrescence is a form of fermentation due to the 

 presence of micro-organisms. He also reasoned from analogy that 

 the relation of micro-organisms to disease was highly probable, and 

 that the changes taking place in the secretion of a wound were 

 probably due to a somewhat similar process to that of fermentation. 

 The probability of micro-organisms being the cause of disease was 

 greatly increased by a momentous discovery from a totally different 

 quarter, an organism having been constantly found invading the 

 tissues and blood-vessels of animals which had died of splenic fever. 

 This was the Bacillus Anthracis, discovered by two observers, 

 Davaine * and Rayer in 1850, though it was ten years later before 

 the complete identification of the relationship of this germ to the 

 disease was definitely established. 



Chronologically this was the first pathogenic Bacillus dis- 

 covered. 



Therefore, at this time, fermentation and putrefaction had both 

 been demonstrated to be due to the action of living organisms, and 

 one of the infectious diseases had been shown to be due to another 

 micro-organism, whilst it had also been demonstrated that neither 

 putrefaction nor fermentation could ensue from mere exposure of 

 susceptible substances to the action of pure air. 



Pasteur had further advanced his belief that the changes taking 

 place in the secretion of a wound were probably due to a process 

 somewhat similar to that of fermentation. 



* Davaine. Recherches experimentalcs sur la Maladie Charbonueuse, par 

 H. Toussaint. Paris : Asselin & Go. 



