134 VASCULAR SYSTEM. 



Q. Why 'are varices rare in foetal life? 



./?. Because the venous coats are very strong at that 

 period; more so in proportion than in after life. 



Q. What alterations take place in the veins of old 

 age? 



*#. A dilatation of their parietes, a diminished contrac- 

 tility in the capillaries, a diminished velocity in the mass 

 of venous blood from an increased capacity in the veins. 



Q. How does Bichat account for the quantity of blood 

 in old age? 



/?. As decomposition prevails over nutrition in ad- 

 vanced life, and the veins receive the decomposed matter, 

 they contain a greater quantity of blood. 



Q. Where are varices principally found? 



A. In the inferior extremities of old persons, and of 

 pregnant women; the causes are obvious. 



Q. Why are the veins enlarged in cancer, fungus, &c.? 



A. The arterial deposition being increased, the venous 

 fulness is in proportion augmented. 



Q. Why is the capacity of the veins enlarged in 

 ascites? 



ft. Because their coats have lost a measure of their 

 elasticity. 



Q. What would be the effect on the circulation, if the 

 blood went from the ventricles by two arterial orifices? 



JL. There would be neither unity of impulse, uniformity 

 of course, or simultaneous pulsation. These are all pre- 

 served by the single aortal trunk. 



Of the Abdominal System with Black Blood. 

 Q. What organs supply this vena portal circulation? 



