Arteriosclerosis in Birds 111 



seen in this case: proliferations of the intimal cells, with con- 

 centric lamellations which completely filled the lumen, hyaline 

 transformation, swelling and necrosis of the media, com- 

 pression of the lumen, medial calcification and ossification. 

 Atheromatous plaques were found in the main vessels. In the 

 observation under review the concentric lamellations and the 

 necrosis of the media produced a compression of the lumen of 

 the vessel which was accompanied by a softening of the brain 

 with subsequent formation of cysts. The coronary vessels 

 showed a high degree of arteriosclerosis. The lumen was often 

 nearly obstructed by intima proliferations. Several infarctions 

 of the myocardium could be seen. 



The present author's suggestion is that only in captivity 

 can such severe forms of arteriosclerosis occur. In nature the 

 animal concerned would have died earlier of hunger since the 

 higher functions of life would have been handicapped. The 

 atherosclerosis induced by several conditions in animals may 

 be reversed by removing those conditions but there is no 

 evidence that the same possibility exists as far as the disease in 

 human beings is concerned. Atheromatosis in the human adult 

 must be considered as irreversible. Atherosclerosis is induced 

 in rabbits and chickens by adding cholesterol in large quan- 

 tities to the food. But animals species differ greatly. The 

 concentration of cholesterol in the blood is a very important 

 factor in atherosclerosis both in the human being and in 

 animal species. Atherosclerosis can be seen in any artery but 

 the major concern is the coronary artery. It is common in 

 young persons, and quite common m persons over 30, but this 

 type of degeneration cannot be seen, or extremely rarely, in 

 animals. 



Arteriosclerosis is of much more importance in human beings 

 than in animals. This fact is important. Unfortunately there 

 is no possibility of studying this disease which so frequently 

 affects the human being, in animal experiments. 



