Conijyarative Poiuer of some Disinfectants. 93 



vaccine and glanders viruses when applied to them in the 

 same manner and in the same strength as is found sufficient to 

 destroy the organisms causing putrefaction, and thus to put 

 a check to that process. The chain of evidence, therefore, 

 seems very complete in favour of these two points — (1) that 

 certain acute contagious diseases are caused by the introduc- 

 tion into, and multiplication in, the animal body of minute 

 vegetable organisms ; and (2) that it is possible to destroy 

 the contagious power of the virus by means of disinfecting 

 agents, and so prevent the spread of these diseases. There 

 may be room for difference of opinion as to what diseases 

 can be included in this class ; but there has been almost 

 absolute demonstration supplied of the correctness of one or 

 both of these points with regard to certain, and among these 

 are to be reckoned especially anthrax, glanders, remittent 

 fever, diphtheria, and vaccinia. When the virus has taken 

 root in the body, it is very questionable if we can do any- 

 thing to stay its progress. This is owing to the fact that we 

 cannot introduce these parasiticidal agents into the animal 

 system, in amount sufficient to destroy the morbific 

 organisms without at the same time doing irreparable injury 

 to the delicate structures of which it is built up. But 

 whilst we have thus to confess our impotence in the present 

 state of our knowledge, and with the agents now at our 

 disposal, I for one cherish the hope that the chemist, by 

 means of the synthetical method of forming new compounds, 

 will yet offer us some agent capable of doing all that is 

 required. That salicylic acid has not done more to supply 

 the want must have been to many, as it was to me, a grievous 

 disappointment. 



We are thrown back therefore on prevention as the great 

 field of our activity in this department of practical medicine ; 

 and there we may with confidence look forward to triumphs 

 greater far than have been already attained, considerable as 

 these are. 



As epidemic diseases generally spread by means of some 

 virus, which has been formed in the body of animals 

 sufifering from them, and is conveyed in some way from 

 these diseased animals to healthy ones, it is clear that if we 

 could destroy with certainty all contagious matters as they 

 leave the body the work of prevention would be done. That 

 it is possible to destroy the viruses of all contagious diseases 

 by mixing them with a sufficient amount of some disinfectant 



