PKACTICAL USE OF SCIENTIFIC RESULTS. 139 



absent for one night after the operation, but generally returning 

 on the second. As I believed the relief produced by the 

 bleeding to be due to the diminution it occasioned in the 

 arterial tension, it occurred to me that a substance which 

 possesses the power of lessening it in such an eminent degree 

 as nitrite of amyl would probably produce the same effect, and 

 might be repeated as often as necessary without detriment to 

 the patient's health. On application to my friend Dr. Gamgee, 

 he kindly furnished me with a supply of pure nitrite, which he 

 himsplf had made ; and on proceeding to try it in the wards, 

 with the sanction of the visiting physician, Dr. J. Hughes 

 Bennett, my hopes were completely fulfilled. On pouring from 

 five to ten drops of the nitrite on a cloth, and giving it to the 

 patient to inhale, the physiological action took place in from 

 thirty to sixty seconds ; and simultaneously with the flushing 

 of the face the pain completely disappeared, and generally did 

 not return till its wonted time next night. Occasionally it 

 began to return about five minutes after its first disappearance ; 

 but on giving a few drops more it again disappeared, and did 

 not return. On a few occasions I have found that, while the 

 pain disappeared from every other part of the chest, it remained 

 persistent at a spot about two inches to the inside of the 

 right nipple, and the action of the remedy had to be kept up for 

 several minutes before this completely subsided. In almost all 

 the other cases in which I have given it, as well as in those in 

 which it has been tried by my friends, the pain has at once 

 completely disappeared. In cases of aneurism, where the pain 

 was constant, inhalation of the nitrite gave no relief, but where 

 it was spasmodic, or subject to occasional exacerbations, it 

 either completely removed or greatly relieved it. It may be as 

 well to note that in those cases in which it failed small bleed- 

 ings were likewise useless. 



From observations during the attack, and from an examina- 

 tion of numerous sphygmographic tracings taken while the 

 patients were free from pain, while it was coming on, at its 

 height, passing off under the intluence of amyl, and again com- 

 pletely gone, I find that when the attack comes on gradually 

 the pulse becomes smaller and the arterial tension greater as 



