VASCULAR SYSTEM. 131 



#. They have; Puschett, a German, has seen them be- 

 come tortuous and longer in disease. 



Q. Are the veins easily or frequently ruptured ? 



fl. They are; for example, the haemorrhoidal, the ce- 

 phalic; even the jugular and cava veins have been ruptur- 

 ed. Call to mind the thin parietes of the cephalic veins. 



Q. Is the venous texture contractile? 



/?. Evidently so. The contractility is slight in the lon- 

 gitudinal, much greater in the transverse direction. 



Q. What circumstances affect this contractility? 



Jl. Seasons of the year, posture of the body, cold or 

 hot applications, and period of life. 



2. Vital Properties. 



Q. Have the veins animal sensibility and contractility ? 



fl. Bichat says that experiments prove them destitute 

 of these properties. 



Q. Does notBeclard allow the veins vital contractility? 



A. Yes; various experiments, he says, prove that the 

 veins in the living, contract in a manner not seen in dead 

 bodies; hence it is a vital, not a textural contractility. 



Q. Do the veins possess sensible organic contractility ? 



/?. They do not; for in disease the veins manifest none 

 of those evidences of increased sensible organic contrac- 

 tility which the heart, stomach, or bladder give out. 



Q. What light does disease throw on the predominant 

 vital forces of our organs ? 



/2. Diseases exalt those that are predominant, so as to 

 show those that prevail in the different organs in health. 



Q. How does Bichat account for the venous pulse ? 



#. He ascribes it to a reflux of blood from the right 



