40 JOURNAL OF THE [April, 



the perpetuity of life would be compromised by the gradual 

 exhaustion of its materials. One grand phenomenon presides over 

 this vast work, the phenomenon of fermentation." It was Pas- 

 teur who first clearly demonstrated that fermentation is always 

 dependent on the life of a microscopic organism : that in fact it 

 is "simply a phenomenon of nutrition." As Professor Tyndall 

 says, in his introduction to the work from which I have just 

 quoted: " with true scientific instinct, he closed with the con- 

 ception that ferments are, in all cases, living things, and that the 

 substances formerly regarded as ferments are, in reality, the 

 food of the ferments ; " or, in the words of M. Radot, " the organ- 

 ism eats one part of the fermentable matter." Here, then, we 

 have two of Beale's physiological elements, a speck of bioplasm 

 and pabulum, translated into a uni-cellular ferment and its 

 fermentable habitat. 



Now, side by side with the new philosophy of fermentation 

 there has developed a revolutionary idea in pathology, which has 

 come to be known as the germ theory of disease. At first this 

 theory was, as usual, pushed to an untenable extreme, in an 

 assertion that all diseases were immediately caused by microbes 

 which were introduced into the system from without and which 

 produced their effects by a direct attack upon the tissues in 

 which they lodged. As a result of the new philosophy of fer- 

 mentation, however, it was soon found that microbes, 

 acting as ferments, produced, by their action upon ferment- 

 able substances, peculiar chemical compounds, resembling the 

 vegetable alkaloids, and which are now called ptomaines. This 

 discovery led to a pretty lively discussion as to whether the 

 microbe or the ptomaine was the immediate cause of the disease 

 which ensued upon the introduction of a microbe into a living 

 body ; and not until a ptomaine had been separated from its 

 associate microbe and, by inoculation, had been caused to pro- 

 duce the disease previously supposed to be dependent on the 

 presence of the microbe itself, was it admitted that, in some 

 cases at least,, the microbe was only an indirect cause of the 

 disease, and the ptomaine was the more immediate. 



It then became apparent that there were still two quite distinct 

 classes of diseases, the infectious, originating without, and the 

 autogenous, originating within, the organism. Plainly the latter 

 did not easily come under the germ theory. It was next dis- 



