1901.] Properties of the Arterial and Venous Walls. 127 



Experiments on the Jugular Vein. 



Strips of vein when heated gave very definite and constant results. 

 Shortening began almost immediately, and went on at first pretty 

 quickly (from the original temperature of 14 — 16° up till about 30°), 

 then more gradually, till at 60 — 65° (usually at 62° or 63°), rapid and 

 very extensive shortening took place, going on commonly till the 

 temperature is above 70°. Subsequent cooling is attended by a decided 

 elongation, though the strip still remains very much shorter than it 

 was to begin with. (Figs. 6, 9, and 10.) 



m 



Fig. 9. — Upper tracing from transverse strip of jugular vein, lower from carotid 



artery of horse. 



Carotid (Ox) 

 (contracted) 



When the temperature is only raised to 40° and then allowed to 

 fall, shortening goes on as before up to that point, and the strip 



K 2 



