270 Dr. C. Bolton. Dropsy produced by [Dec. 19, 



The arterial blood-pressure was registered by means of a mercurial 

 manometer, the cannula being placed in either the carotid or femoral artery, 

 and a float, which traced the pressure curve on a kymograph. 



The venous pressures were taken in the inferior vena cava, the cannula 

 being introduced into the external iliac vein ; at the lower end of the femoral 

 vein where it divides into two branches at the ankle, the cannula being inserted 

 into one of the branches and pushed on until its point was flush with the 

 opening into the femoral vein ; in the portal vein, the cannula being intro- 

 duced into a branch of the splenic vein, the spleen being then placed back in 

 the abdomen ; at the upper end of the external jugular vein, the cannula 

 being inserted into the posterior auricular vein and pushed down until its 

 point was flush with the opening into the jugular vein. The venous pressure 

 was registered on the kymograph by means of an air tambour connected with 

 the top of the venous manometer by means of rubber tubing. This simply 

 demonstrates whether a rise or fall of venous pressure occurs : it is no 

 indication of the exact amount of such rise or fall. The diameter of the 

 inferior vena cava is 5 mm., that of the superior vena cava practically the 

 .same or a trifle smaller, and that of the portal vein 4 mm. 



2. Effects of Obstruction of the Superior Yena Cava. 



(a) Upon the Production of Dropsy. 



The vein was obstructed both above and below the entrance of the azygos 

 vein {i.e., between the entrances of the internal mammary and azygos veins, 

 and between the azygos vein and the right auricle). 



Obstruction below the Azygos Vein. 



Complete Occlusion. — In each case death resulted either on the day following 

 the operation or five or six days later. The post-mortem findings were the 

 same in ail cases. There was marked oedema of the mediastinum, extending 

 up into the neck and down along the inferior vena cava to the diaphragm, 

 the whole of the cellular tissue being distended with clear serous fluid. A 

 slight amount of clear fluid was found in the pericardium, and bilateral 

 hydro thorax was present. In one case 25 c.c. serous fluid was found in each 

 pleural cavity ; sometimes this fluid is blood stained. The oedema of the 

 mediastinum may extend through the diaphragm, and out as far as the axillae. 

 There is no free fluid in the abdomen. (Edema at the seat of the wound 

 occurs in the subcutaneous and muscular tissues, but this is not continuous 

 with the mediastinal oedema and is dependent upon mechanical laceration of 



