150 Disturbances of Circulation. 



tion wound into the jugular vein, or which is accidentally intro- 

 duced in intravenous injection, becomes mixed with the blood in 

 the form of bubbles of various sizes. In case of healthy animals 

 with normal blood pressure, moderately large quantities of air (5 

 to 10 cubic centimeters in dogs, sheep, horses) injected into the 

 jugular vein are sometimes born without harmful results, the air 

 disappearing quite rapidly by absorption in the circulating blood. 

 In animals . with low pressure and a tendency to accumulation in 

 the right heart (as after operations and after loss of blood in 

 parturition) the air bubbles are apt to accumulate in the right 

 heart and form a large elastic air cushion which is not forced 

 onward by systole, being only compressed by cardiac contraction 

 and expanding again in diastole. In consequence the blood is 

 dammed back in the right heart, and there results a marked dilata- 

 tion of the right ventricle, reaching two or three times its normal 

 volume. (Death takes place from the cardiac dilatation and suf- 

 focation, the blood being prevented access to the lungs. Accord- 

 ing to Frangois Franck it may also be possible that some of the 

 air passes through the lungs, and, traversing the left heart into 

 the coronary arteries, brings about embolic occlusion of the latter 

 and anaemia of the myocardium.*) 



Fat ciiibolism is usually met in connection with severe con- 

 cussive lesions of the bone marrow (Ribbert). The occurrence of 

 fracture of a bone with such concussion allows lacerations of the 

 delicate walls of the venous capillaries to take place, after which 

 fat droplets from the fat cells abundantly present in the marrow 

 may pass into the blood (Ribbert). Access of fat into the blood 

 may also be thought possible from the liver cells in case of con- 

 tusion .of this organ, its cells also being usuall\' rich in fat (Rib- 

 bert). The oil droplets are first carried with the venous blood to 

 the lung, where they lodge in the small arteries and capillaries, 

 the capillary network often appearing turgid as if filled with a 

 fatty injection mass. From the occlusion thus brought about 

 haemorrhagic infarcts are formed in the lungs, usually a transient 

 condition (may be proved by injecting a fat emulsion into the 

 jugular). The liquid fat may. however, pass through the pulmon- 

 ary capillaries and be carried on into the left heart, whence it may 

 be conveyed with the aortic blood into the cardiac musculature 

 (coronary arteries), the renal glomeruli, or the brain and other 

 organs. The fat lodged in the coronary arteries, just as any other 



*Recueil veier. 1903, p. 370. 



