1 6 TOXINS AND ANTITOXINS. 



made regarding them. In 1888 Roux and Yersin,* 

 in their beautiful researches on diphtheria, pointed 

 out the diastatic nature of the properties of the 

 active albuminoid matter existing in the cul- 

 tures of the specific bacilli of this disease. From 

 that period, these products began to take a more 

 and more prominent place, from year to year, in 

 the study of pathological affections, and, by develop- 

 ing the knowledge of immunity, they have opened 

 a new path to the investigations of therapeutic 

 technic. 



It is due to the knowledge of these principles that 

 we have learned that the infectious microbes, far 

 from acting as they were believed to do only a few 

 years ago, and which Pasteur strongly maintained 

 to be by vital parasitism — such as would be the 

 case with the carbonizing bacteria which, according 

 to Pasteur, act by diverting the oxygen, or causing 

 capillary embolisms — owe their pathogenic action 

 to the toxic substances which are the products 

 of their secretion, and which spread throughout 

 the organism, even though the microbe frequently 

 is localized in a very circumscribed spot, as in 

 tetanus and in diphtheria. 



The idea of intoxication by these products has 

 now replaced the idea of the direct action of the 



* Roux and Yersin: Memoir? sur Dipht^rie. Ann- Inst, 

 Pasfgur, i888-;889. 



