1901.] Properties of the Arterial and Venous Walls. 137 



not aware that any other tissue or structure has been shown to give a 

 tracing of this sort. 



These results are strikingly different from those of Wertheim,* 

 Eoy,t and others; these workers employed (chiefly or exclusively) 

 strips of aorta in which little muscular tissue is present, frequently 

 taken from the human subject some considerable time after death 

 (from various diseases). Their tracings show a diminishing amount 

 of elongation for unit weight, the same result that I have obtained in 



Fig. 18. — Carotid (ox), contracted. Transverse strip; 8 hours p.m. Second 

 loading after interval of If hour. 



the aorta and pulmonary artery. Some of Eoy's curves are at first 

 nearly, though not quite, straight in the early part of their course, 

 i.e., the elongation was during that part nearly, though not quite, 

 proportional to the stretching weight : then a more marked and pro- 

 gressive diminution in extensibility becomes evident. 



In some of my tracings the increment of length caused by the appli- 

 cation of the first weight is very small — the smallest of an increasing 

 series ; in other cases the first extension is more considerable, and is 

 followed by a very small one, to which others succeed in progressively 

 increasing series. As regards the extent of the first elongation much 

 seems to depend on the exact arrangement of the strip before the first 

 weight is applied, and on the degree of its curvature, &c. 



In some instances when a strip of artery taken not very long after 



* Loc. cit. 



f ' Journal of Physiology/ rol. 3, p. 125. 



