1/6 BACTERIOLOGY. 



spleen which function as huge devouring 

 cells or " macrophages." 



The existence of animal parasites, especially 

 Tcenice and Gregarinidce, in fishes has been 

 known for some time ; vegetable parasites, such 

 as Saprolegnia, have also been known; and like- 

 wise the fact that some of the internal organs 

 of fish, particularly the sexual organs, are poi- 

 sonous. Mosso discovered that the blood of 

 the eel is poisonous, and the poisonous quality 

 of putrid fish has also been ascertained. Fischel 

 and Enoch found in 1891, while working in my 

 laboratory, that fishes, too, can succumb to bac- 

 terial infection. They discovered that a disease 

 affecting carp is a sort of septicaemia accom- 

 panied by numerous haemorrhages. The accom- 

 panying bacteria were endosporous, grew upon 

 gelatin, agar, blood-serum, potato, and rice, and 

 stained by Gram's method. It was then estab- 

 lished for the first time that these bacteria form 

 the same proteid-like poison while growing as 

 parasites in the animal body, which they pro- 

 duce saprophytically in cultures. The bacteria 

 and spores, freed from poison, infected carp, 

 mice and guinea-pigs, and the animals all 

 perished from septicaemia. The poison itself 

 was also injurious to dogs, which sickened 

 with diarrhoea in the same fashion observed in 

 the " carp cholera." Emmerich and Weibel 



