88 



Scientific Proceedings (52). 



tudinal slot (6 mm. wide and 25 mm. long) is fitted with a lubri- 

 cated rubber tube (4 mm. internal diameter) so as to occlude the 

 longitudinal slot. To produce aortic insufficiency, the metal 

 catheter with its rubber obturator is introduced, free from air 

 and without hemorrhage, into the left subclavian artery and 

 aorta. The catheter is so adjusted by palpation that the valves 

 close about it near the middle of the occluded slot in the catheter. 

 The inner rubber tube may now be connected directly with a 

 manometer. 1 Aortic pressure records with Frank's manometer 

 show that a catheter of such size that it can be introduced into 

 the subclavian does not impede the systolic discharge so as to 

 cause stenosis in the physiological sense. By drawing out the 

 obturating rubber tube to such an extent that the slot is opened, a 

 valveless circuit with a minimal resistance is established between 

 aorta and ventricle. The intraventricular pressure may still be 

 recorded. 



Upon entirely withdrawing the metal catheter, normal con- 

 ditions are restored. By inserting the catheter through the auricu- 

 lar appendage, the method may be used to induce mitral regurgi- 

 tation. Postmortem examination of six hearts showed no damage 

 of the valves. 



The advantages of being able to produce temporary valvular 

 insufficiencies are several : 



1. It permits the consecutive demonstration of all valvular 

 lesions and their circulatory effects on the same animal. In such 

 a series of demonstrations we produce mitral and tricuspid stenosis 

 by simple invagination of the auricular wall into the auricular 

 ventricular openings with a finger. 



2. By subsequently reestablishing normal conditions, it per- 

 mits a control of the reflex circulatory and respiratory disturbance 

 incidental to the production of experimental valvular lesions. It 

 is quite possible for such reflex effects to entirely overshadow or 

 complicate the mechanical effect of the lesion and, unless so 

 controlled, the results cannot be considered comparable to clinical 

 lesions. 



1 In the case of Frank's optical manometer, the connection can be made rigid 

 and without elastic connection. 



