SCIENCE IN MEDICINE 241 



bodies (alexines) which have an affinity for, and are able to 

 destroy, bacteria. 



Metchnikoff 1 and the French school stoutly upheld the 

 theory that the bacteria are destroyed by being eaten up by 

 the phagocytic white cells — the macrophages and microphages 

 — and did not attribute any of the action to the serum. 

 Though in the light of recent work they have had to modify 

 their views to a considerable extent, they still consider the 

 white blood cells to be the essentially important agents, and 

 attribute any action of the serum to the fact that it contains 

 substances set free from the cells. But, granting the presence 

 of these bodies in the serum, their origin is still a matter of 

 doubt. Metchnikoff considers them to be products of the 

 phagocytes, whilst many followers of Buchner in Germany deny 

 the cells any part in their manufacture. Without pursuing this 

 difficult and complex question any further, we will briefly touch 

 on those substances in the serum, as yet discovered, which have 

 anti-bacterial properties, and then consider how they may be 

 used in the treatment of bacterial infections. 



Contemporaneous with the inquiry into the origin of the 

 protective substances of the blood, further varieties of anti- 

 bacterial substances were discovered. 



B cider ioly sins. — Pfeiffer, working on cholera, was the first to 

 show in an unmistakable way that cholera bacilli introduced 

 in enormous quantities into the peritoneal cavity of immunised 

 animals were in the space of a few minutes entirely dissolved. 

 These substances, whose action is thus demonstrated, are 

 technically known as Bacteriolysins. 



Agglutinins. — These were first discovered by Durham 

 working, in Gruber's laboratory, on typhoid in 1895. They 

 cause the bacteria to swell up, to lose their motility, and finally 

 to aggregate into clumps. This does not take place in the case 

 of all bacteria, and for all practical purposes is limited to cases 

 of typhoid and Malta fever when running a favourable course. 

 Widal and Grunbaum applied the experiment to clinical medicine, 

 and since then the agglutination test has proved of great value 

 in the diagnosis of both typhoid and Malta fevers. The degree 

 of agglutination may further be taken as a useful guide as to 

 the patient's progress, at all events as regards the manufacture 

 of protective substances. 



1 Lemons sur la PatJiologie comparce de V inflammation, 1892. 



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