CHAPTEK V. 



THE BACTERIAL POISONS OF SOME OF THE INFECTIOUS 

 DISEASES. 



We will now give our attention to the chemical poisons, 

 both the ptomaines and the proteids, of some of the infec- 

 tious diseases, and in doing this we will illustrate and sub- 

 stantiate the statements made in the preceding chapter. 



ANTHEA.X. — The definition of an infectious disease, as 

 we have given it, is well illustrated by the facts which have 

 been learned concerning the caiisation of anthrax, whicli 

 has probably been more thoroughly studied than any other 

 infectious disease. Kausch tauglit that this disease has its 

 origin in paral^'sis of the nerves of respiration. As to the 

 cause of this paralysis he gave us no information. Delafond 

 thought that anthrax has its origin in the influence of the 

 chemical composition of the soil affecting the food of ani- 

 mals and leading to abnormal nutrition. The investigations 

 of Geelach in 1845 demonstrated the contagious nature 

 of the disease, which was emphasized by Heusinger in 

 1860 and accepted by Virchow in 1855. However, as 

 early as 1849, Pollbndee found numerous rod-like micro- 

 organisms in the blood of animals with the disease. This 

 observation was confirmed by Brauell, who produced 

 the disease in healthy animals by inoculations with matter 

 taken from a pustule on a sick horse. Attempts were made 

 to ridicule the idea that these germs might be the cause of 

 the disease, and it was said that the bodies seen were only 

 fine shreds of fibrin or blood crystals. Some claimed that 

 the rod-like organisms reported were due to defects in the 

 glass, while others claimed that the defects existed in the 

 eye of the observer, and others still suggested that the de- 



