194 Nil RITE OF AMYL IN ANGINA PECTOUIS. 



turbance of the regulating apparatus of the heart, as normally 

 the increased tension acting on the roots of the vagvis should 

 slow the pulse. It has been suggested to me (by Professor 

 Ludwig) that the pain in the heart may be due to irritation of 

 its sensory nerves by the great pressure of the blood, and 

 that in the right arm and neck may be due to the same 

 cause acting on the arteries, those of the right side being pos- 

 sibly contracted more than the left. Whenever the tension was 

 lowered by nitrite of amyl the pain disappeared from the 

 greater part of the cardiac region, the neck and the arm, but 

 sometimes remained persistent ht a point about 2 inches to the 

 inside of the right nipple. This I think indicates that the tension 

 in the right ventricle was not yet relieved, and the small volume 

 of the pulsa (see Tracing 3, May 17th, Fig. 119) seems to show 

 that the amount of blood passing through the small pulmonary 

 vessels at each systole was small, probably from contraction of 

 their lumen. So long as this condition remained the pain was 

 almost certain to return. It is possible that the right ventricle 

 might not be able to empty itself completely at each systole, 

 v/as therefore quickly refilled, and consequently contracted 

 frequently, forcing the left ventricle to contract with it, and 

 producing the rapid pulse with small volume seen in Tracing 3 

 of May 17th, Fig. 1'19. The influence of the small vessels of 

 the lungs over the circulation, though in all probability of 

 extreme importance, is a subject of which we know as yet 

 almost nothing. 



The question whether the contractile power of either ven- 

 tricle is lessened during the attack is one which cannot be 

 decided with certainty from the present tracings. Digitalis 

 which has been recommended on the supposition that the 

 heart is weak during the attack, proved productive in this case 

 of more harm than good, contracting, as it does, the small 

 vessels. 



We may, I think, conclude that (1) the attack in the present 

 case consisted in a spasmodic contraction of some, if not all, of 

 the small systemic, and probably of the pulmonary vessels, 

 causing great increase in the blood-pressure in both sides of the 

 hsart, such as is found in animals after division of the vagi; 



