Page:The Harveian oration 1888.djvu/27

19 trimethylamine N (0113)3, dimethylaniine NH (0113)2 and tri- ethylamine N (C^HJg, cadaverin C^H^gN^, putrescin C^Hj^N^, saprin C^Hj^N^ and mydalein. The amount of these substances obtained depending upon the stage of decomposition and the temperature at which it took place. I will not stop to describe the poisonous effects of these products' on the system. For that I must refer you to Professor Brieger's publications or to Dr A. M. Brown's treatise on the animal alkaloids. The point of interest is that they are developed during the process of putrefaction in which bacilli take an active part; and probably it is from the development of these poisons that the effects on the animal system are produced when certain of the micro-organisms gain an entrance into it. It is to be observed, that these poisons are developed by the action of bacilli on dead or effete animal matter; not necessarily on living tissue; and it might be suggested therefore that if they are produced from living tissues by the microorganisms, this can only take place when the tissue has lost its so-called vitality or when there is a departure in the tissue from the normal condition which constitutes health. But this will hardly apply to such a disorder as splenic fever, or even to tuberculosis in guinea-pigs, &c., in which cases we have very clear evidence that the introduction of the pure cultivated microorganism into healthy animals will produce the disease. This at once suggests the question, Can the apparently innocuous or non-pathogenic bacteria be so cultivated outside the body as to develope an intense virulence and become pathogenic — endowed, that is, with the power of growing and multiplying within a living animal 1 To this I will briefly refer later on.

Now, not only has it been demonstrated that certain poisons or ptomaines can be derived from dead putrefying animal sub-