upon the Animal System. 17 



involuntary muscles, the heart continuing to act after the sus- 

 pension of animal life and the cessation of the diaphragm and 

 lungs, and the left ventricle distributing dark-coloured blood 

 through the body. The absorption of the gas itself thus ap- 

 pears to act like a subtle poison ; and as in cases of mere 

 exclusion of common oxygenated air, when respiration is 

 suspended for a longer period, the speedy restoration of the 

 action of the diaphragm and lungs, and the introduction of 

 atmospheric air, appear to offer the surest method of recovery ; 

 and the substitution of warmth and friction for the destructive 

 use of tobacco injections and bleeding is essential. Bichat 

 and Chaussure having found that the application of galvanism 

 in cases of immersion in the gas of privies produces a depo- 

 sition of sulphur, confirms the result of my experiment as to 

 the entrance of sulphuretted hydrogen into the circulation. 



V, EXPERIMENTS WITH HYDROGEN GAS. 



A kitten of about a fortnight old was placed under a glass 

 vessel of hydrogen gas. It fell dead in less than half a minute, 

 after gasping and struggling, and on being removed into the 

 air it recovered. Another kitten of the same brood, being 

 similarly immersed, was affected in the same manner, but 

 having lain about three minutes in the gas, after falling insen- 

 sible, it did not recover in the open air. It was then opened, 

 and the circulation was found to be stopped, the right ventricle 

 being distended with dark blood, and the brain and lungs 

 collapsed. A frog was immersed in hydrogen, but it exhibited 

 no signs of inconvenience. In the morning it was found dead, 

 and the blood was uniformly dark coloured. 



Several sparrows were immersed in hydrogen, and they fell 

 dead in two or three seconds. On opening them the circu- 

 lation was still, the right ventricle distended with dark blood, 

 and the brain and lungs collapsed. 



The hydrogen gas appears in these instances to be admitted 

 through the bronchial tubes, and, like the preceding gas, to be 

 destructive in the same manner as certain poisonous substances 

 act upon the centre of the nervous system. It is remarkable 

 in the experiments with hydrogen, that no contractility could 

 be excited by mechanical irritation in the heart and bowels. 

 The renewal of atmospheric air in the lungs within the space 

 JAN.—MARCH, 1830. C 



