280 Dr. C. Bolton. Dropsy produced by [Dec. 19 ? 



Dropsy of the pleurae and peritoneum is regularly found if the inferior cava, 

 he constricted to a diameter of 3 mm., the superior to that of 3 mm., and the 

 azygos vein he ligatured. 



This is a more easy method of producing uncompensated heart disease in 

 an animal than is constriction of the pericardium, because the exact amount 

 of constriction is known at the time of operation, and it does not depend 

 upon the judgment of the operator, so that there is less fear of the animal 

 dying or of the operation being unsuccessful. 



(b) Upon the Circulation of the Blood. 



In these experiments the inferior vena cava was constricted to a diameter 

 of 3 mm., and the superior vena cava was completely ligatured. 



The same results are obtained whether the azygos be ligatured or not. 



The effects upon the arterial and venous pressures are exactly the same 

 as those produced when the pericardium is constricted, with the exception 

 that the rise of venous pressure is most marked in the external jugular vein, 

 because the superior vena cava is completely obstructed. 



The arterial pressure falls considerably, and the venous pressure in all parts- 

 of the body rises. The venous pressure falls to the normal level again in 

 about the same time as it does when either vein is constricted separately, and 

 dropsy is produced whilst the venous pressure is normal. 



The effects of obstruction of both superior and inferior venae cava? are, 

 therefore, precisely the same as those produced by an uncompensated heart 

 lesion. 



6. Production of Hydremic Plethora after Obstruction of the 

 Inferior Vena Cava. 



If the inferior vena cava be constricted, and if, after the pressure in the 

 external iliac vein has fallen to its normal level subsequently, salt solution 

 be very slowly injected into the external jugular vein in quantities of 5 c.c. 

 at a time, a large amount may be introduced without raising the venous 

 pressure behind the constriction or the arterial pressure. If during the 

 injection the venous pressure rises 10 mm. MgSG 4 solution (less than a 

 pressure of 1 mm. Hg), it quickly falls again after the injection. In this way, 

 during one and a-half hours I have injected 130 c.c, and still the pressures, 

 arterial and venous, remained normal. Absorption of lymph occurs much more 

 slowly than this, and the composition of lymph is different from that of salt 

 solution. It is therefore inconceivable to me how an animal by absorption 

 can raise its capillary pressure by the production of hydremic plethora. In 

 the case in point 10 c.c. ascitic fluid was found in the peritoneal cavity at the 



