96 



is only infective when mixed with some of the secretions of a 

 patient already affected. This accounts for persons being 

 affected from drinking water from wells into which there is 

 soakage from closets, or from a reservoir polluted by sewage, 

 or from drinking milk supplied from some distant dairy where 

 patients are suffering. Here in Adelaide, only a few months 

 ago, the Central Board of Health traced twenty-three cases of 

 typhoid to a dairy where a child was ill with the disease. In 

 all these instances there must have been something capable of 

 infecting the water or the milk, and this must have been some- 

 thing having the property of growing and increasing in the 

 medium in which it existed. If this be not a micro-organism I 

 must leave it to others to determine its nature. "We are all 

 interested in the discovery of the causes of that devastating 

 malady — cholera — which now and again sweeps across Europe 

 like a plague from its Indian home. Our newspapers have 

 told us that the German Government sent Koch to Egypt, and 

 afterwards to India, to investigate this disease. It is humiliat- 

 ing that a foreign Government should undertake a work which 

 England ought long ago to have taken in hand ; but we are 

 none the less thankful for the light which Koch's observations 

 have thrown on this disease. These observations have led to 

 the discovery of a bacillus in the intestines of cholera patients 

 which sufficiently differs in shape from others, as in Koch's 

 opinion, to be distinguishable. It is thicker at one end than 

 at the other, and being curved resembles a comma. Hence it 

 is called the comma bacillus. The same bacillus was found in 

 a tank from which the patients had drawn their supply of 

 water. It could be cultivated like the other Bacteria, but for 

 obvious reasons it could not be experimented with on human 

 beings, and as cholera is not a disease of the lower animals the 

 crucial test is not available. Koch found that this bacillus 

 lias a peculiar mode of development under cultivation ; it has- 

 not been observed to form spores, and it is easily killed by 

 absence of moisture. Supposing them to be the cause of 

 cholera, we have the consolation of knowing that if they once 

 become dry there is no further danger. Koch has given demon- 

 strations before a Commission in the South of Erance, and this 

 Commission confirms most of Koch's conclusions. Our British 

 Grovernment has lately sent Klein and Gibbes to India to- 

 make further investigations, and we await with more than 

 ordinary expectation the result of their work. 



There is another discovery of Koch's which has an interest 

 in every part of the world where consumption or tuberculosis 

 is known. Ever since I can remember there has been a suspic- 

 ion in the medical mind that consumption is sometimes infec- 

 tious. Within the last few years our German confrere dis- 



