CONCEENING THE EFFECTS OF "TUBA" FISH-POISOX. 13 



weakening of the muscle is removed b} 7 washing out the poison. 

 "Weaker solutions have no action on voluntary muscle. 



In the experiments on the tongue the poison was injected 

 under the mucous membrane. Induction shocks were used to 

 stimulate the muscle. 



Effects on Involuntary Muscle. " Tuba " poison in solu- 

 tions 1 in 60 to 1 in 6,000, diminishes the tone and movements of 

 the involuntary muscle of the intestine of a monkey. This weaken- 

 ing is counteracted by the presence of a dilute solution of sodium 

 carbonate. 



Effects ox Heart Muscle. " Tuba " poison, even in strong 

 solutions, has no action on heart muscle. The isolated heart beats 

 strongly and for a long time in Ringer's solution containing the 

 poison in concentrations 1 in 8 or 1 in 100. The same results are 

 obtained when the heart is perfused with the poison 1 in 80. 



These results with heart muscle, verify the fact that for some 

 time after the respiration has ceased in the living animal under 

 the influence of the poison, the heart may be felt still beating 

 strongly. 



Effects ox the Blood. Strong solutions (1 in 100) of the 

 poison in Ringer's solution alter neither the red nor white cells of 

 the blood of the monkey. The white cells show the usual amoeboid 

 movements if the solution be kept warm. There is no haemolysis 

 or breaking up of the red cells. 



The oxygen capacity of the blood is not altered by the poison, 

 the red cells taking up oxygen easily and giving it off easily. 



Effects ox the Blood Vessels. Solutions of the poison 

 varying in strength from 1 in 30 to 1 in 4000 were perfused through 

 the blood vessels of a toad. In most cases the poison dilates the 

 blood vessels, in a few cases no effect is produced. 



In another series of experiments the extract (from 1 in 50 

 up to 1 in 1250) was perfused through the blood vessels of a limb 

 of a monkey. In these vessels dilatation is produced and the 

 poison so affects the blood vessels that the power of adrenalin to 

 constrict them is markedly lessened and in most cases abolished. 



Experiments on Anaesthetised Monkeys. 



Macacus cynomolgus and Macacus nemestpinus were the mon- 

 keys employed, chloroform being used as the anaesthetic. The 

 poison was injected into a vein, usually the femoral vein, by means 

 of an injection cannula ; records of the blood pressure, usually that 

 of the femoral artery, and of the respiration were taken. 



Injected in this way the extract from 1/50 gm. of the root 

 is sufficient to produce death. In all cases marked effects are 

 produced on the respiration and blood pressure (Fig. 1). Respira- 

 tion is usually stimulated at first, then depressed and finally para- 

 lysed. The blood pressure falls considerably but only temporarily. 



R. A. Soc, No. 73, 1916. 



