G. NATURAL HISTORY AND ZOOLOGY. 287 



valve in each cardiac revolution. The sphygmosystole is the 

 interval between the opening and the closing of the aortic 

 valve in each cardiac revolution. 



The author commences by giving a table of measurements 

 that strongly substantiate the law previously published by 

 hi 111 : namely, that the length of the cardiosy stole is constant 

 for any given pulse rate, but varies as the square root of the 

 length of the pulse beat. A similar series of fresh measure- 

 ments shows that the length of the sphygmosystole is con- 

 stant for any given pulse rate, but varies as the cube root of 

 the length of the pulse beat. These laws apply to all the 

 arteries examined by him, and must, therefore, equally apply 

 to the aorta itself, and this gives him the means for deducing 

 the relation between the whole cardiac-systolic act and the 

 time during which the aortic valve remains open. He then 

 deduces (from an earlier-published series of measures) the 

 time required by the second or dichrotic wave of the pulse 

 in traveling from the aortic valve to the wrist, and thence is 

 able to conclude that the earlier primary wave takes the 

 same time in going the same distance ; which conclusion is 

 shown to be justified by the agreement to the third place of 

 decimals of measurements which have been arrived at inde- 

 pendently, and which is great evidence in favor of the accu- 

 racy of the methods and arguments employed. The author 

 then gives some results obtained by the employment of a 

 double sphygmograph, by means of which simultaneous trac- 

 ings are taken from two arteries at very different distances 

 from the heart. It is shown that the time occupied by the 

 pulse wave in traveling the distance of twenty-three and one 

 half inches, or the difference between the wrist and ankle 

 pulse, is 0.0012 of a minute, or 0.07 of a second of time, in a 

 pulse of 75 per minute. This interval varies very little with 

 difference in pulse rate, but it is proved that there is a mark- 

 ed acceleration of the pulse wave as it gets farther from the 

 heart. 12 A, IX., 514. 



NEW EXPERIMENTS ON THE VENOM OF EAST INDIAN SERPENTS. 



Drs. Fayrer and Brunton have communicated to the Roy- 

 al Society of London an important memoir upon the patho- 

 logical action of Indian poisonous snakes, the experiments 

 having been conducted in London with venom sent to En- 



