192 NITRITE OF AMVL IN ANGINA PECTORIS. 



by unavailing efforts to overcome this obstacle. Nothnagel* 

 •states that during angina there is pallor and coldness of the 

 extremities, small pulse, and other symptoms of a cramp-like 

 •contraction of the systemic arteries, and that the spasm is 

 relieved by remedies which cause their relaxation, such as warm 

 baths and friction. 



It is quite possible that the pathology of all cases classed 

 under angina pectoris is not the same, and that the differences 

 of opinion are not due merely to the want of exact methods of 

 observation. What the nature of the attack was in the present 

 oase may be learned to some extent from an examination of the 

 sphygmographic tracings, which were begun by direction of Dr. 

 Maclagan, and continued during the time the case was in the 

 wards under the care of Dr. Bennett. In taking these tracings, 

 the instrument, which was one of Marey's, without any means 

 of estimating the pressure employed, was applied to the arm 

 above the end of the radius, as it was found to cause pain when 

 applied over the bone for any length of time. The amplitude 

 of the curve thus obtained is greater, and it did not occur to me, 

 ^ till after studying the physiology of the circulation under Pro- 

 (^ fessor Ludwig, that in such cases as the present, wliere sudden 

 " changes occur in the vessels, I was increasing the fallacy which 

 the variation in the height of the lever from turgescence of the 

 tissues produces, and which may be confounded with a rise 

 from increased tension in the vessels. Except where marked 

 otherwise, the tracings were all taken with the patient in a 

 - recumbent position, and neither the cord by which the instru- 

 ment was attached to the arm, nor the screw regulating the 

 pressure, was touched during the observation. 



The case excited considerable interest, and was carefully ob- 

 served and commented on by Professor Bennett to the clinical 

 class, and the cardiac lesion was diagnosed by him from the 

 physical signs to be aortic obstruction and regurgitation, with 

 dilatation of the aorta, but no sacculated aneurism. 



The tracings confirm this diagnosis, showing in a typical 

 manner the abrupt ascent, terminating in a hook, of each wave, 

 characteristic of the unfilled arteries, which aortic regurgitation 



* Beiit. Arch.f. Tclin. Med., vol. iii, 309 j Chit. med. Wiss., vol. v, 715. 



