46 (2 1 6) Society for Experimental Biology and Medicine. 



Similarly it was thought sufficient to study mechanical injuries 

 of the heart-valves rather than to attempt their production with the 

 aid of bacteria. Therefore, while the actual lesions were studied 

 in the museum and histologically, the injuries to the valves were 

 produced by cutting the valves with a special blunt hook having a 

 knife edge on the inner side of the curve. The pressure relations 

 were then rendered visible to the students by the curves traced in 

 inks of different colors from cannulas inserted at various points in 

 the circulation. Stenoses were produced by the application of a 

 screw clamp about the orifice of the heart concerned and tracings 

 taken in a similar way. These experiments are similar to those 

 described by v. Basch and Moritz, but they are not subject to the 

 criticism that they are made on a model of glass and rubber. 



Murmurs could be heard and traced very accurately by the use 

 of a stethoscope with very small bell, which could be applied di- 

 rectly to the ventricles or along the vessels. Thrills could be felt 

 and the dilation and excessive activity of any portion of the circu- 

 latory apparatus directly observed. In this way there were pro- 

 duced and studied aortic stenosis and insufficiency, mitral stenosis 

 and insufficiency, pulmonary stenosis, and tricuspid stenosis and 

 insufficiency. 



Lesions of the myocardium were simulated both by the mechan- 

 ical destruction of the muscle substance and by the injection into 

 it of such coagulating substances as alcohol, and the effects studied 

 by the same method. Obstruction of various branches of the 

 coronaries was also studied in detail. 



The effect of the closure of various blood vessels was demon- 

 strated as well as the effect of the dilation and contraction of capil- 

 laries in different regions, and the character of the capillaries of 

 the lungs in this respect was studied. The mode of obliteration 

 of blood-vessels after ligature and the accomodative changes which 

 take place when the blood-supply is diminished and when collateral 

 circulation is demanded were also considered. 



The short course ended with the study of aneurysm, arterio- 

 sclerosis, and the experimental formation of thrombi and of infarcts 

 on the introduction of foreign bodies as emboli. 



The advantage which accrues to the student seems to be chiefly 

 in his obtaining an intimate and first-hand knowledge of all the 



