92 



Messrs. J. A. Gunn and R. St. A. Heathcote. 



This fact is mentioned only because time effects and possibly even quanti- 

 tative effects of the venom cannot be gauged with the same accuracy on the 

 intestinal muscle as on the perfused heart. There is also more irregularity in 

 the quantitative results on different segments of intestine than one obtains 

 in the perfused heart. This is true of other substances, e.g., adrenaline, as 

 well as of cobra venom. 



The following summary, however, shows that, in spite of these drawbacks, 

 the effects of cobra venom on the intestine of the cat differ sufficiently, and 

 sufficiently uniformly from its effects on the intestine of the rabbit to allow 

 of conclusions being drawn from the experiments. 



With the rabbit's intestine, a solution of 1 in 10,000, 1 in 20,000, and 1 in 

 25,000 caused tonic contraction of the gut with arrest of the movements in a 

 few minutes, and 1 in 50,000 stopped the movements in the same fashion in 

 half an hour. "With the cat's intestine, a solution of 1 in 5,000 caused a 

 slight preliminary rise of tone, which gradually passed off and the movements 

 ceased in a position of relaxation in 25 minutes. 1 in 10,000 caused relaxa- 

 tion of the gut, sometimes marked, but did not arrest the movements in half 

 an hour ; 1 in 20,000, 1 in 25,000, and 1 in 50,000 caused slight relaxation, 

 but had very little effect on the amplitude of the segmentation movements, 

 which were still vigorous at the end of half an hour. The experiments with 

 each concentration were repeated twice. 



In figs. 3 and 4 is shown a comparison of the differences on the rabbit 

 and cat intestine of cobra venom 1 in 10,000. 



These experiments therefore show that there is both a quantitative and a 

 qualitative difference in the action of the venom on the intestine of the rabbit 

 as compared with that of the cat. The quantitative difference consists in 

 the fact that much higher concentrations are required to kill the intestine of 

 the cat than to kill that of the rabbit, and the qualitative difference in the 

 fact that the type of effect differs somewhat in the two animals. In the 

 rabbit the venom always causes arrest of the intestinal movements in systole, 

 while in the cat the venom usually produces increased relaxation. 



Red Blood Corpuscles. 



Experiments were made on washed red blood corpuscles of the cat and rabbit. 

 A 4 per cent, suspension, twice centrifuged and washed, was used in each 

 case. The saline solution used was 0"9 per cent, sodium chloride in distilled 

 water. The venom solution was made by dissolving the venom in the saline 

 solution. This venom solution was divided into two parts, one of which was 

 used for the experiment on rabbit's corpuscles, the other for that on cat's 

 corpuscles. This obviated experimental errors in weighing and differences in 



