J^. Bacteriological Imrestlgatlons of Poiaonoas Flahea 



The toxicity of poisonous fishes is not due to bacteria. It was, of 

 course, hardly necessary for me to confirm the fact that the poiaon result- 

 ing from putrefaction after death is due to bacterial action, but as I was 

 ordered to do so I performed the following experiment. The materials used 

 were eight kuchiku. three morays, and three balloonfish. As controls three 

 goatflsh and thi^e Pecapterus op. were used, making a total of twenty fish 

 employed in the experiment. 



The fish Tiers first opened up with a sterilized scalpel and scissors and 

 all of the viscera were removed. A platinum wire was then used to plant cul'=' 

 tures on both Endo plates and agar plates. The cultures were left at room 

 temperature (26° average) for twenty-four hours. 



Almost no bact'firial colonies were seen in the cultures from the livers, 

 gonads, kidneys, and muscles. The colonies which were seen developed on the 

 cultures from the inside of the intestines. In general definite colonies 

 were formed, ttoen a microscopic examination was made of colonies which were 

 thought to differ, twenty- five stocks were distinguished!?]. 



These bacteria were in general glossy bacilli which did not turn the 

 Endo medium red. They were Gram-negative and most of them possessed mobility. 

 Few of them broke dovm lactose, and although they broke down grape sugar they 

 did not generate gas. Seven strains broke down glucose. Few of them coagu- 

 lated milk, eight strains liquefied gelatine, and none of them formed indole 



Prom these results it was not possible to detect any strains of bacteria 

 peculiar to poisonous fishes. 



After the bacteria were isolated they were cultiMced through fo'ir — five 

 generations (transplanted once every three weeks) on agar slopes. 

 These cultures were used in experiments on representative experimental animals. 

 The fluid used in the innoculations was prepared by floating the requisite ' 

 amount of bacteria from a culture gi^jwn on an agar slope for 20 hours at 37**C. 

 in a physiological salire solution, and 0.5 ml of this preparation was injected 

 into the body cavity of a mouse weiring 12-13 grams. The toxicity was 

 Judged by whether or not the animal was alive at the end of 4.8 hours, i'he fol- 

 lowing table shows the results; 



194 



