450 ZOOLOGY AND MEDICINE. 



one has further doubt but that certain symptoms in infectious dis- 

 eases are caused by noxious substances eliminated by the microbes. 

 Can such a proposition be made more general? Do Helminthes and 

 other animal parasites produce analogous substances? How active 

 are they, and how far may we attribute to them certain morbid 

 phenomena? Yes; without doubt parasites of an animal nature 

 behave in the same manner as do bacteria, and it is truly surprising 

 that this has not been sooner recognized.'' 



I find a very convincing example of this in malarial fever, the 

 febrile exacerbation being, in my opinion, merely the result of an 

 intoxication of the organism. It may be demonstrated in this way: 

 The hematozoon, Avhich lodges, increases, and multiplies in the 

 interior of a red-blood corpuscle, obeys the common rule — that is to 

 say, it assimilates substances foreign to its own organism, and, at the 

 same time, disassimilates and rejects about it soluble refuse matter. 

 This accumulates in the interior of the globule and is not shed into 

 the current of the blood until the globule bursts. At first it is too 

 much diluted to be active, but its quantity increases, as does the num- 

 ber of parasites, and soon it produces a first febrile condition. It is 

 generally supposed that the fever becomes more and more violent 

 if it is not treated Avith quinine; that is to say, that the toxines are 

 discharged into the plasma in greater and greater quantities. This 

 example is, I think, sufficiently characteristic; it has at least the 

 merit of being taken from a disease whose course is known to every- 

 one, and, besides, it is the only rational explanation of the febrile 

 phenomena. 



In view of this, it is not surprising to find that the trypanosomata 

 also produce toxic substances to which we must attribute some of the 

 symptoms of the sleeping sickness, in particular the somnolence 

 characteristic of that malady. It is already known that the Bothrio- 

 cephalus sometimes causes progressive pernicious ana?mia, not be- 

 cause it occasions an intestinal hemorrhage, but as a consequence 

 of the absorption of substances which it excretes, and which are 

 voided into the intestine; we suspect that other Helminthes may be 

 similarly effective in a greater or less degree. Here, then, there is 

 opened an entirely new chapter in chemical physiology and we may 

 say that it now appears to be beset with the most serious difficulties. 



In bringing these questions before you I do not pretend to have 

 shown all the aspects in which zoology is related to medicine. The 

 union of these two sciences becomes every day more close. Sir 

 Patrick Manson said to me one day, " The time is near at hand when 

 every school of medicine will have a chair of zoology; in France 



a R. Blauebard, Substances toxiques prorluites par les parasites auimaux. 

 Archives de Parasitologie, X, p. 84, 1905. 



