1865.] restoring the Life of Warm-blooded Animals, -c. 365 



if by this means the heart could be stimulated to active contraction. In 

 other instances water heated to a given temperature was injected, or the 

 vapour of water. Again, electricity was brought into play ; and, lastly, 

 various mechanical contrivances were introduced, either for forcing the 

 blood over the system or for drawing it over. 



Injection of oxygen. In. respect to the effect of oxygen gas, I found 

 that when the gas freshly made from chlorate of potassa, but well washed, 

 was driven into the venous current towards the heart by the vena cava su- 

 perior, the auricle and ventricle of the right side at once exhibited active 

 contraction, which could be prolonged for an hour without difficulty by 

 simply continuing the introduction of the gas at intervals ; but the contrac- 

 tion of the ventricle was never sufficient to produce a pulmonic current. 

 When the gas was injected into the arteries, the current being directed 

 towards the heart, so as to charge the structure of the heart itself with the 

 gas through the coronary arteries, the heart in one instance made active 

 movements which could be distinctly felt through the chest wall ; but the 

 effect was only momentary ; and after it was over, the organ was found 

 distended with gas and devoid of irritability. In another case, on making 

 a post-mortem examination of an infant that had been dead twelve hours, 

 oxygen gas at a temperature of 96 was injected into the heart. The organ 

 became gradually distended ; and on the left side, both in the auricle and 

 in the ventricle, tremulous muscular action, like very feeble contraction, 

 was distinctly seen. Whether this was due to the mechanical entrance of 

 the gas or to true muscular contraction excited by the presence of the gas, 

 is perhaps open to question, but I could make no distinction between this 

 contraction and ordinary contraction as it is elicited immediately after death. 

 The subject of this experiment was fourteen days old. Previous to the in- 

 jection there had been no cadaveric rigidity, but after the injection this 

 phenomenon was well marked. 



Injection of peroxide of hydrogen. The experiments with the peroxide 

 of hydrogen were varied by passing the solution very slowly into the lung 

 through the trachea, so that the oxygen that would be liberated might come 

 into contact, together with the air afterwards introduced by the bellows, 

 with any blood remaining in the pulmonic circuit. A little fluid during 

 this process found its way into the left auricle through the pulmonary 

 veins, and the auricle thereupon contracted. On injecting the peroxide, in 

 another experiment, over the arterial system, the blood on the venous side 

 was pushed forwards into the heart and it was made red in colour from 

 absorption of the oxygen. As the fluid found its way round the systemic 

 circuit, vigorous muscular contraction of the pectorals, of the muscles of 

 the neck, and of the diaphragm followed, but there was no reaction of the 

 heart. 



Oxygen excites muscular action. I gather from these researches that 

 oxygen, introduced into the circulation directly, possesses the power of 

 calling forth muscular contraction. This power seems to be due to the 

 combination of the oxygen with a little blood remaining in the circulatory 



