OF THE VENOM OF THE RATTLESNAKE. 85 



and, as usual, the heart began to boat with excessive rapidity, but with such feeble- 

 ness as to raise the mercurial column in the cardiometor only five or six milli- 

 metres at each systole. With so feeble a beat it would have been difficult to 

 estimate any such slight increment of feebleness as might at first be produced by 

 the venom. Reluctantly, therefore, this method, which had promised so much, was 

 abandoned. I finally succeeded by resorting to the method detailed in the follow- 

 ing cases, which I have chosen for record here, as being sufficiently illustrative of 

 the series to which they belong. 



Experiment. — A small black and yellow cur-bitch was secured as usual. The 

 pulse was 140 ; respiration 29. The trachea was opened, and a tube placed in it. 

 Next, the medulla oblongata was destroyed by pithing, during which about four 

 ounces of blood were lost. Respiration instantly ceased, and the heart-pulse rose 

 to IGO. Artificial respiration was now made about forty times in the minute. 



The femoral artery was opened, and the cardiometer tube fitted in it, and secured 

 at 5.20 P. M. The constant of arterial pressure was sixty millimetres, the heart 

 beat raising the column from six to twenty millimetres. During three or four 

 minutes these numbers remained about the same, and accordingly a standard of 

 comparison having thus been attained, the dog was bitten twice in three minutes 

 by two snakes of large size. In the next two minutes, the column fluctuated be- 

 tween sixty-seven and seventy-five millimetres, thus giving but eight millimetres 

 to represent the heart force. The change was so notable, that my assistants sup- 

 posed a clot might be forming, and the tube was therefore removed, cleansed, and 

 replaced. It was perfectly patent, and the artery was unobstructed. 



Six minutes after the bite, the constant was forty millimetres, with ten milli- 

 metres of rise at each systole. At the eighth minute, the constant was thirty mil- 

 limetres, the rise fifteen millimetres. This was, however, the maximum, and 

 usually the heart force was but four to five millimetres. The constant was now 

 rapidly falling. The heart beat very irregularly, never raising the mercury above 

 twelve millimetres. There was usually one strong pulsation, and then four feeble 

 ones, of two to four millimetres. 



The quivering about the wound continued very remarkable throughout the obser- 

 vation. Upon studying this case, it appeared that the heart and the constant of 

 arterial pressure were both affected very early, but I was not disposed to regard all 

 the ultimate eftects as due to the venom. In a case so removed from normal phy- 

 siological conditions, and so surrounded with causes of depression, it was only 

 possible to draw nn inference from the occurrences of the first few minutes after 

 the introduction of a new element — the bite of the snake. 



Additional observations, similar to that just recorded, went equally to show 

 that the heart loses power in the first stage of Crotalus poisoning, and that the 

 constant arterial pressure undergoes a rapid and singular diminution. Considera- 

 tions above stated, would have induced me to question still more rigidly the results 

 of experiments of so complicated a nature, were it not that they are so well sup- 

 ported by all the preceding evidence, and by the numerous records of symptoms in 

 cases of venom poisoning in man. 



It is proper to add that in some instances of death, in rabbits, for example, arti- 



