12 PROCEEDINGS OF THE ACADEMY OF [Biolog. 



they are fasting, but suffer no ill effects when the vao is given during digestion. 

 That this protection is not due to a mere mixture of the vao with the food of 

 the full stomach, is shown by the fact that rabbits, whose stomachs are always 

 more or less distended with food, are protected only when owing to the entry 

 of fresh food, digestion becomes active. 



4. The demands of the system for water do not affect to any perceptible ex- 

 tent the absorption of vao from the stomach of the rabbit. 



5. The circulation of the frog is arrested within from ten minutes to one 

 hour by the introduction of vao under the skin. The same result obtains 

 within from twenty-four to forty-eight hours, when the poison is .swallowed in 

 small doses. 



6. The first effect of vao is to increase the force of the heart without increas- 

 ing the number of its pulsations. 



7. The next effect is a paralysis of the musciilar tissues of the heart, so that 

 the ventricle stops first, and the right and left auricles next, in the order in 

 which they are named. In a majority of the frogs poisoned by vao, the heart 

 remains galvanically irritable for a certain time after the organ has ceased to 

 pulsate. 



8. The heart stops before the voluntary motions are at an end, in all-cases 

 of rapid poisoning. When poisoning occurs by absorption from a mucous sur- 

 face, the phenomena march more slowly, and voluntary control and reflex 

 power are both lost before the heart has entirely ceased to beat. 



9. Vao stops the respiration in warm-blooded animals by arresting the cir- 

 culation, and so paralyzing the nervous system, without which respiration is 

 impossible, so that the checked respiration is a consequence and not a cause 

 of the injury to the cardiac functions. 



10. In'the batrachia also, the respiratory movements cease before the heart 

 has entirely lost the power to pulsate. 



11. In the alligator poisoned by vao the respiration is perfect some time after 

 the heart is at rest. 



12. The facts last quoted and the inability of artificial respiration to restore 

 or sustain the cardiac movements in warm-blooded animals poisoned by vao, 

 prove sufficiently that the first effect of the poison is upon the heart, and that 

 the appearances of asphyxia observed post-mortem in rabbits, cats, etc., are of 

 secondary importance so far as concerns the cause of death. 



13. The temperature of warm-blooded animals poisoned by vao falls with 

 considerable rapidity, and does not undergo any elevation after death. 



14. The nerves of sensation first lose their power to convey impressions the 

 motor nerves are next affected. The paralysis of the nerves extends from the 

 periphery to the centre. The affection of the nervous system may be due to 

 the sudden arrest of the circulation, and not of necessity to the direct in- 

 fluence of the vao. The irritability of the voluntary muscles in the frog is 

 lost much-earlier than is the case when the animal dies by decapitation. 



15. The sympathetic nerve is paralysed, at least in the upper portion of its 

 distribution, before the nerves elsewhere have lost their functional power. 



16. The ciliary motion is unaffected by the use of vao. 



17. The blood of animals thus poisoned coagulated as usual, and had not 

 lost the power of changing color when exposed to oxygen or carbonic acid. 



18. So far as we are aware, no true physiological antidote exists for vao 

 poison, since even artificial respiration fails to sustain life in animals affected 

 by it. 



19. The vao poison olosely resembles corroval in its physical, chemical, and 

 physiological reactions. The alkaloids extracted from the two poisons produce 

 in. animals of equal size effects which cannot be distinguished. 



20. We, therefore, are inclined to consider vao as merely a weaker variety of 

 corroval, and to conclude that the apparent difference in the effects produced 

 by the original extracts is due to a difference in their strength. 



[May, 



