198 SCIENCE PROGRESS. 



chloride of iodine especially was found to possess a distinctly 

 curative power. At the time this was ascertained the 

 advocates of two rival theories as to the origin of immunity 

 were engaged in hostile criticism. Metchnikoff, the founder 

 of the doctrine of phagocytosis, and Behring, who held to 

 the bactericidal properties of such fluids of the body as 

 blood serum and lymph, were in direct scientific antagonism, 

 which led to renewed researches into the question of im- 

 munity, and resulted in an epoch-making discovery. Beh- 

 ring conclusively showed that in several diseases, among 

 which diphtheria was included, serum yielded by the blood 

 of an animal rendered artificially immune exerted no bacteri- 

 cidal action upon the bacillus of the disease, but was appar- 

 ently capable of destroying the toxins produced by the 

 bacillus. Antitoxic bodies are therefore presumably present 

 in the blood of animals which are made immune, and serum 

 from such an animal can be both protective and curative; 

 an already developed disease can be permanently arrested 

 by the introduction of serum charged with antitoxins. 

 Upon this discovery, which is undoubtedly the greatest 

 contribution that bacteriology has at present rendered to 

 practical medicine, rests the treatment of diphtheria by 

 antitoxic serum. The details just briefly mentioned have 

 been known for years, and the recent interest which has 

 been aroused is due to the evidence adduced by Roux in 

 favour of the value of serum as a therapeutic agent at the 

 recent Congress of Hygiene in Buda-Pesth. 



It is a purely medical question whether the mortality of 

 the disease under treatment diminishes by antitoxic serum, 

 but sufficient evidence has now been collected to convince 

 the most sceptical that the subcutaneous injection of serum is 

 a valuable therapeutic agent. The various preparations of 

 serum obtained in this country and from abroad differ con- 

 siderably in antitoxic power, and also in the dose which 

 should be employed. A recent paper by Janowski (19) 

 deals fully with the variations in strength of the prepara- 

 tions employed by Behring, Roux and Aronson. The 

 remedy is harmless, though a transient inflammation of the 

 skin, which may be accompanied by slight pains in the 



