18 Proceedings of the Royal Physical Society. 
acid, or benzoyl chloride, with all of which more stable 
compounds of the ptomaines are formed. 
It was further found that Pasteur’s observations as regards 
fermentation could be applied to the formation of these 
ptomaines, and it was found that, just as in the case of 
brewing of beer, it was not only the food substance that 
determined the nature of the ptomaine formed, but also the 
kind of micro-organism that grew in the food. Thus whilst 
some yeasts would give rise to the pure alcoholic fermentation, 
others gave rise to a bitter taste in the beer, whilst some 
organisms again give rise to butyric fermentation, and others 
produce lactic acid. It thus became possible to understand 
how certain diseases could be produced by the vegetative 
activity of the organism in the body giving rise to the 
formation of poison which could so far paralyse the protoplasm 
of the cells that the organisms were allowed free play to 
develop and ultimately overcome their host. This, however, 
proved the stepping-stone to the rationale of preventive 
inoculation, and however these preventative inoculations may 
be ultimately explained in different cases, and there are many 
various theories as to how this occurs, we may confidently 
anticipate that we are now on the eve of a general system of 
inoculation against the specific infective diseases, diseases 
that have hitherto proved intractable to the treatment of both 
physician and surgeon. 
We have before us a period in which controversy as to the 
action of micro-organisms in the body, and the various 
methods of combating these, will be most thoroughly discussed 
and experimented upon, and we may safely prophesy that 
during the next few years certain departments of prophy- 
lactic and hygienic medicine will be entirely revolutionised. 
At present the methods of treating patients suffering from, or 
liable to suffer from, micro-organisms through their accidental 
introduction, may be divided into four, and it may be well 
here to formulate briefly the essential points of these various 
methods. In the first of these, as an example of which may 
be taken inoculation against anthrax or small-pox, we seek, 
by introducing a modified poison, or minute doses of the 
virulent poison, to habituate or acclimatise the cells and 
