CONTRACTION OF PULMONARY CAPILLARIES. 331 



into the jugular vein. The same mistake has probably been 

 made by Gianuzzi,* who attributes a convulsive action to the 

 drug. By injecting the solution into the peritoneal cavity^ 

 however, I found that it had no action whatever even when 

 used in large quantities, while a solution of strychnia applied 

 in the same manner would have acted nearly as strongly as- 

 when injected into a vein. 



(c) By Contraction of the Pulmonary Capillaries. — When 

 contraction of the pulmonary capillaries is produced by a drug 

 injected into the veins, the venous blood is hindered from 

 reaching the left side of the heart, and the left ventricle and 

 arterial system become empty, and the arterial pressure sinks- 

 while the right ventricle and venous system become swollen 

 and turgid. The alteration of the blood-pressure in the 

 arterial and venous systems may be measured by manome- 

 ters connected with tliem ; but while the arterial fall in the 

 pressure is easily observed, there is considerable difficulty in 

 measuring that in the veins, due to the rapid formation of 

 coagula in the tube which is pushed down the jugular vein 

 into the vena cava. 



Another method is, to open the thorax and note the colour 

 of the lungs and the comparative fulness of the right and left 

 sides of the heart, and of the venous trunks, before and after 

 injection of the drug. The animal is first narcotised, and a 

 cannula placed in the trachea. The skin and cellular tissue are 

 then divided along the middle of the sternum and reflected on 

 each side. The muscles are then divided along the line of the 

 costal cartilages, and artificial respiration is begun. The 

 abdominal muscles are then separated from their attachment 

 to the sternum and costal cartilages ; the latter are cut through,, 

 except the first, which is left untouched in order to avoid 

 wounding the internal mammary artery, and the sternum i& 

 bent upwards and retained in its position by a hook. In the 

 rabbit, it is generally unnecessary to tie any vessels, as the 

 bleeding stops quickly of itself ; but if any one should bleed 



* Gianuzzi and Bufalini, Ricerche eseguite nel Gahinetto di FisioJcgia della 

 Universita di Siena, pp. 71-86 ; abstracted in the Centralblatt fixr die Med, 

 TFiss., 1873, p. 824. 



