xxiv Proceedings of the Royal Society of VictoHa. 



also, that from the mere fact of a cow feeding on garbage of 

 various kinds, its milk may acquire infective properties. If 

 there were such different ways whereb}^ the milk of cows is 

 rendered infective, I can hardly think that it would be so 

 difficult to get proof of the occurrence of outbreaks due 

 unmistakably to contaminated milk. Since the Jolimont 

 case, about ten years ago, there has not been a single 

 instance traced out in this City, and my own experience 

 has compelled me to conclude that milk contamination is 

 actually a rare mode of spreading contagion, no single 

 instance having come under my notice during my term of 

 service as Health Officer of the City. 



It is different, I believe, with another mode by which 

 typhoid is spread, viz., as a result of bad or defective 

 drainage. I have often been satisfied that there was no 

 other cause in operation adequate to account for severe and 

 persistent local outbreaks of the disease. Evidence has 

 actually been supplied that the tyi^hoid bacillus may live 

 in ordinary well or river water ; and the close association 

 often found to exist between typhoid and sewer emanations 

 supplies a strong probability, amounting almost to certainty, 

 that they may live, and possibly multiply, not only in 

 cesspits, drains, and sewers, but also in soil soaked with 

 sewage matters. The bacilli have not been found in, and 

 would be difficult to isolate from the combination of bac- 

 terial forms which find lodgment and breeding ground in 

 sewage matter ; but if they do happen to be present there, 

 it is almost a certainty that they would escape in the 

 currents of foul air which rise from the outlets of town 

 sewers. Such air does contain many bacterial forms, as 

 has lately been proved by the investigations of Dr. J. D. 

 Robertson {British. Medical Journal, 15th December, 1888). 

 He did not find on his cultivation plates the bacillus of 

 typhoid, doubtless, as he says, because there were no 

 epidemics at the time of his observation ; but he did 

 recognise that in sewer air there is a larger proportion of 

 bacilli compared with other organisms, than in the open 



