FiTf'HETT. — Physiological Action, of Tutin. 311 



near the surface and emitting air-bells, while at this time the other two 

 fish showed quivering movements of the trunk. In two hours and three- 

 quarters the small fish was dead. In three hours the larger one was dead, 

 and the medium-sized one died in five hours. So that 0-0132 per cent, 

 picrotoxin killed all the fish in five hours. Meanwhile the fish in the equi- 

 molecular solution of tutin began to show symptoms at the end of three 

 hours and three-quarters, which continued till late at night — twelve hours 

 after the exj)eriment was begun. The next morning two were found dead 

 (between twelve and twenty-two hours after the experiment was begun), 

 and the last one (medium-sized) died at twenty-four hours (Exp. 106). So 

 the result shows that in equimolecular solutions picrotoxin is more lethal 

 than tutin. 



One must be cautious, however, in applying these results to the case of 

 mammals. In fishes the swim-bladder regulation is disturbed both by 

 picrotoxin and by tutin, and of the two, picrotoxin seems to have the 

 greater influence, for air-bells are more frequently seen to be emitted by 

 fish subjected to the action of this drug. The swim-bladder — of such para- 

 mount importance in the case of fishes — has no analogue in mammals, and 

 it is therefore quite probable that the lethal power of these poisons may be 

 reversed in this class of animals. Indeed, the experiments on cats (Exps. 4, 

 168, 169, 171) justify this statement. 



(c.) Effect on Fishes of Tutin Solution that has been hydrolysed. 



It has been a constant observation in the case of both lower animals 

 and of human beings that tutu poisoning is more lethal when the stomach 

 is empty. This suggested the possibility of the toxicity of the tutin being- 

 increased by the action of the hydrochloric acid in the stomach. Experi- 

 ments on fishes were therefore undertaken to test this. To 8 or 10 c.c. of 

 a 0-5-per-cent. solution of tutin an equal amount of 0-4 per cent, hydro- 

 chloric acid was added, and the mixed fluid kept at a temperature of 37° C. 

 for different lengths of time in difierent experiments. It was then exactly 

 neutralised with a solution of soda of corresponding strength, and made up 

 to 1,000 c.c. 



In the first experiment (Exp. 92) of this kind 7 c.c. of tutin solution was 

 so treated (0-0035 per cent, tutin), and a control (Exp. 91) of a solution 

 of untreated tutin in corresponding strength was used. In the hydro- 

 lysed tutin solution one fish showed symptoms at three hours and three- 

 quarters, which continued till it died, at seven hours and a half. Another 

 began to show symptoms at eight hours and one-third, and died between 

 ten and twenty-two hours ; while the third showed symptoms at nine hours, 

 and died at 22| hours. In the control of untreated solution one fish showed 

 symptoms at four hours and died at four hours and a half, and the other 

 two, of which one showed symptoms from the seventh to the tenth hour, 

 recovered. 



Another experiment of the same kind was then made, a slightly higher 

 percentage of tutin being used — viz., 0-004 instead of 0-0035. Two test- 

 tubes were taken, each containing 8 c.c. of a 0-5 per cent, solution of tutin. 

 To one, A (Exp. 94), 8 c.c. of 0-4 per cent. HCl were added ; so that the 

 total percentage of HCl in the fluid was 0-2. This mixture was kept at 

 37° C. for one hour, then neutralised and made up to 1,000 c.c. To the 

 S'c.c. tutin solution in the other test-tube B (Exp. 95) the same amount 

 of HCl was added, but it was immediately neutralised, and then kept at 

 37° C. for one hour, and made up to 1,000 c.c. In each of these two solu- 



