Graphic Study of Heart Murmurs. 179 



benzyl effect with the vasodilator action of the nitrites and the 

 author decided to study the pharmacology of benzyl nitrite in this 

 connection. Benzyl nitrite is a definite chemical compound de- 

 scribed by a number of chemists. It is a yellow liquid, boiling at 

 115I 0 to 116 0 C. at 35 millimeters pressure. The drug is slightly 

 soluble in water, but freely soluble in alcohol. While pure benzyl 

 nitrite rapidly decomposes on exposure to the air, alcoholic solu- 

 tions of the same keep fairly well. Laboratory experiments with 

 benzyl nitrite revealed the typical benzyl effects on smooth 

 muscle organs both in vitro and in vivo. The effect on blood 

 pressure showed a rapid fall, but unlike the case of sodium nitrite 

 and nitroglycerin the vaso dilatation was of much longer duration. 

 The toxicity of benzyl nitrite is not very great, but on intravenous 

 injection the nitrite effect on the blood is manifested after large 

 doses (100 millimeters per kilo weight of dog or cat). An alcoholic 

 solution of the drug has been administered to a number of patients 

 by mouth for the relief of excessive hypertension. The results 

 so far obtained have been very satisfactory but the investigation 

 has not yet been completed and further work on the subject is 

 in progress. 



88 (1670) 



New method for graphic study of heart murmurs. 



By HORATIO B. WILLIAMS. 



[From the Department of Physiology, College of Physicians and 

 Surgeons, Columbia University, New York.] 



Methods hitherto in use have proved unsatisfactory for re- 

 cording murmurs, except such as are loud and low-pitched or 

 of a sustained musical character and not very high-pitched. 

 Einthoven's method, in which a carbon microphone is used, gives 

 murmur records which are often more complicated than the sounds 

 themselves, a circumstance which appears to be due to lack of 

 damping in the moving parts of the microphone, especially of the 

 carbon particles. In most microphones the diaphragms have a 

 natural period too low for best results, but the undamped motion 

 of the carbon particles is the most serious drawback. The 



