317 



MONDAY, DECEMBER 11, 1865. 



The Yeey Eey. Chaeles Geaves, D. D., President, in the Chair. 



Mr. W. H. Hardinge read a paper " On the Irish Transplantation 

 of A. D. 1653-54 ; and on the Extent, Yalue, and Distribution of the 

 Lands forfeited in Ireland.' ' 



Mr. "W*. Handsel Geiefiths read the following paper : — 



On ILeiiodeomometees. 



Theee has long been a question among physiologists as to the velocity 

 with which the blood moves in the arteries. Many of them have made 

 calculations which, had they come from others than men of such repute, 

 would have excited derision ; and indeed we can scarcely refrain from 

 smiling when we read that Hales "inferred the velocity of the blood 

 at the commencement of the aorta in man to be at the rate of 735 

 feet per second." 



The celebrated Volkman saw the folly of the deductions drawn from 

 such vague data as these were, and he devised an instrument, which 

 he termed the " Hsemodromometer," the object of which was to measure 

 the velocity of the movement of the blood in the arteries. 



The results of experiments made with this instrument were, of 

 course, much more reliable than those founded on calculations inferred 

 from data of the most vague and uncertain character ; but, while I 

 would unhesitatingly give the preference to the deductions drawn from 

 experiments with Yolkman's Hsemodromometer, I can by no means as- 

 sent to the supposition that they are correct, or even nearly so. The 

 use of Yolkman's instrument involves great objections ; and, although I 

 look on the instrument itself as a model of ingenuity, I cannot regard 

 it as one on which I should depend for a solution of the problem, With 

 what velocity does the blood move in the arteries ? 



I will proceed to describe as briefly as possible the construction and 

 mechanism of Yolkman's Hsemodromometer. I will then consider the 

 objections which I entertain to it; and it is but right that I should 

 afterwards mention how I would propose to rectify these defects. 



Yolkman's Haamodromometer consists essentially of a glass tube, 

 which is bent into the form of a hairpin, and is fifty- two inches 

 long. This tube is filled with water ; and, by a peculiar arrangement, 

 is placed between the open ends of a cut vessel. For a concise de- 

 scription of this instrument, I beg to refer to Todd and Bowman's 

 " Physiological Anatomy," vol. ii, page 364. In the drawing which 

 is given in that work is represented a tube, which is constructed of 

 metal, and measures one inch and a half in length ; it terminates 

 at cones, which fit into other cones, by which means they are adapted 

 to the cut ends of the vessel. The mechanism of the stopcock is 

 indeed an admirable contrivance; and, although easily understood, 



K. I. A. PEOC. VOL. IX. 2 U 



