300 Professor J. Bunion Sanderson [May 15, 



nature ; whereas pathology admits nothing to be a contagium unless 

 it can be observed in action as such. For one thing, at all events, 

 we may be grateful to the Jena botanist. It was for the purpose of 

 investigating his theory that those indefatigable cholera workers, Drs. 

 Lewis and .(Cunningham, were sent to India, where, although they spent 

 more time and labour in correcting Hallier's mistakes than it took 

 Hallier himself to fall into them, they were thereby aflbrded opportunity 

 of acquiring information of the highest practical and scientific value. 

 It would take too long to refer to other efforts in the same direction, 

 but it may be readily understood that the question of the material 

 cause of cholera was too important to be neglected, and that as soon 

 as cholera seemed once more to threaten Europe it again urgently 

 claimed the attention of scientific pathologists. Accordingly, in 

 1883, Dr. Koch, who is the author of two of the greatest discoveries 

 of modern times in relation to spreading diseases, was deputed by 

 the German Imperial Government to proceed to Egypt, and then to 

 India, to investigate cholera. 



Stated in few words, the result of Dr. Koch's inquiries were — 

 (1) That the x in cholera has the form of a curved rod, which 

 Dr. Koch likens to a comma (as written, not as printed) ; and (2) 

 That the disease (cholera) is caused by the presence, growth, and multi- 

 plication of this organism in the apparatus for absorption contained 

 in the lower part of the small intestine, and by the consequent 

 formation there of an animal poison which produces the collapse and 

 the other fatal effects of cholera. 



These statements, as soon as they became publicly known, assumed 

 a very great importance, because they appeared to afford support to 

 a doctrine with which they have no necessary connection — namely, 

 that of the communicability of cholera by direct personal intercourse 

 with the sick. The mere fact of the existence of countless myriads 

 of organisms of a particular form in the intestinal liquid, although 

 very interesting in itself, affords no evidence that they are tlie 

 culprits, unless two other things can be proved respecting them — 

 namely, that they possess the power of producing cholera wherever 

 they exist, and that they are capable of maintaining their life, not 

 merely within the intestine, but also in the soil: for, as we have 

 seen the evidence that the material cause of cholera is capable of 

 existing outside of the body and of spreading over the world inde- 

 pendently of the presence of persons affected with the disease, is so 

 conclusive, that no explanation of cholera can be accepted which 

 does not take this into account. 



Now in India the question of the prevention of cholera is a very 

 practical one. Here, cholera is chiefly a question of preserving life ; 

 in India it is one of commerce, and consequently of national 

 prosperity. If it were believed in India that the cholera patient is 

 himself a source of infection, that each individual comma is a source 

 of danger, India would be compelled to adopt prophylactics of the 

 same kind as tliose which were adopted last year by the ignorant 



