372 NITRITE OF AMYL IN THE COLLAPSE OF CHOLERA. 



pulse became normal, as well as its character, I felt nearly 

 certain that the spasmodic pain would speedily return with all 

 its former intensity. 



The observation of Drs. Hayden and Cruise that the pulse 

 became perceptible in their patients after the inhalation, seems 

 to show, however, that the nitrite did relax the pulmonary 

 vessels during the collapse, and allowed a fuller stream of blood 

 to pass into the left ventricle, and thence to the body. Why, 

 then, did it increase the difficulty of breathing ? One would 

 have thought that by allowing more blood to flow through the 

 lungs, it would at least have alleviated this symptom, if it did 

 not remove it altogether. The experiments of Dr. Arthur 

 Gamgee at once enable us to answer this question. In a paper 

 in the Royal Society's Transactions,^ he showed that nitrite of 

 amyl combines with haemoglobin, the oxygen-carrier of the 

 blood, and prevents it from giving off oxygen after it has taken 

 it up. "When the blood is exposed to the vapour of the drug as 

 it passes through the lungs, the oxygen becomes locked up in it, 

 and cannot be given off to the tissues for their use, so that 

 however much oxygen the blood in the arteries may contain, it 

 acts very much as if it were venous. In consequence of this, I 

 have found that when the vapour of the nitrite is passed into 

 the lungs of rabbits, they are seized with suffocative convul- 

 sions. The greater part of the blood which passed through the 

 lungs having been acted on by the vapour, it affects the brain 

 just as it would have done if the trachea had been closed, and 

 no air allowed to come near it during its passage through the 

 pulmonary vessels, and therefore convulsions occur as soon as it 

 reaches the brain. Professor H. C. Wood, of Philadelphia,t 

 who has lately written a valuable paper on the action of the 

 nitrite, found no convulsions after injecting it subcutaneously. 

 By giving it in this way, the blood was not acted on during its 

 passage through the lungs, and asphyxia was prevented. This, 

 I think, shows that if nitrite of amyl is to be used at all as a 

 remedy in cholera, it must be given internally or by subcu- 

 taneous injection, and not by inhalation. This mode of admini- 



* Philosophical Transactions, 1868, p. 589. 



t American Journal of Medical Sciences, July, 1871. 



