RELATION TO INFECTIOUS DISEASES. 89 



diseases being due to chemical poisons. In investigating 

 this theory, three possibilities suggest themselves : 



(a) The microorganisms themselves may be poisonous, 

 or the poison may be an integral part of them. Neelsen, 

 at one time an advocate of this theory, thus accounted for 

 the appearance and increase in violence of the symptoms as 

 the germs increase in number. In order for the conditions 

 of this theory to be fulfilled the microorganisms must be 

 present in the blood before any of the symptoms appear. 

 But in anthrax the most thoroughly studied of all the in- 

 fectious diseases, and the one to which all these theories 

 have been applied, the bacilli first appear in the blood, as a 

 rule, only a few hours before death, and long afiber the 

 appearance of the first symptoms ; while in many other 

 diseases the germs are never found in the blood. More- 

 over, as HoPPA has shown, if this theory be true, the in- 

 jection of a large quantity of anthrax bacilli directly into 

 the blood should be followed immediately by symptoms of 

 the disease, and death should be speedy. But he found, on 

 making experiments of this kind, that the symptoms did 

 not appear until from twenty-four to seventy-two hours. 

 Nencki found by analysis that the substance of the an- 

 thrax bacilli resembles vegetable casein in some respects, 

 and animal mucin in others. This " anthrax protein " is 

 freely soluble in alkalies, is insoluble in water, avetw acid, 

 and the dilute mineral acids. It contains no sulphur and 

 was believed by Nencki to be inert ; but the recent re- 

 searches of BuCHNEE has shown that this belief is not well 

 founded. It has been stated by a number of investigators 

 that suppuration might be induced by the injection of cer- 

 tain sterilized cultures, but the dictum of Weigert, " no 

 suppuration without bacteria," has been generally accepted ; 

 and statements to the contrary, although some of them have 

 been made by men of excellent reputation, have until recently 

 received but little credence. However, Buohner has shown 

 conclusively that the albuminate of the bacterial ceil in as 

 many as seventeen different species possesses well-marked 

 pyogenetic properties, and that the pus formed is free from 

 germs. Buchner separated the microorganisms from the 



