The opinion of the most profound workers in the so-called “germ diseases” is, that these diseases are really due to the pathological effects of chemical substances (ptomaïnes) elaborated and secreted by certain micro-organisms. That is, a given contagious disease is rather the result of one or more compounds formed by the life-history of a micro-organism, than the mere presence of that micro-organism itself. By looking at certain cases in the above light, we can well understand why persons suffering with cholera die so rapidly. The alkaloid or ptomaïne (discovered by Pouchet in 1885) which the Comma bacillus secretes or forms is rapidly absorbed into the blood, long before the bacillus itself is capable of being absorbed by the mucous membrane of the intestine, and then into the blood. It is a well-known fact that most micro-organisms multiply with great rapidity in the media in which they live, and if particular organisms can be destroyed, the harmful effects of the products produced by their life-histories will not increase, and the disease will soon be at an end.