The pathogenesis of transient focal cerebral ischemia.

"UT ITH the growing appreciation of the vast clinical importance of coronary thrombosis the question is being asked more and more whether the atherosclerotic changes in the vessel wall are the chief causal factor or whether there are other factors, such as changes in the character of the blood itself, that play an important role. Unfortunately the question cannot be answered at present. There are various reasons for thinking that other factors may play a part in the production of thrombosis, but upon the evidence at present available we are forced to believe that atherosclerotic changes in the arterial wall are an essential, and probably are the chief, prerequisite for the formation of the thrombus."' This statement was written by Dr. Lewis A. Conner, editor of the American Heart Journal, and appeared in an article in the American Journal of the Medical Sciences in 1933. If one were to change the word "coronary" to "cerebral," this statement would be directly applicable to our current knowledge of the pathogenesis of focal cerebral ischemia. As a clinician, Dr. Conner may have wondered why knowledge of occlusive cerebrovascular disease lagged behind that concerning coronary occlusive disease. This lag was probably explained in part by the neurologists' and neuropathologists' intense interest in cerebral morbid anatomy and in efforts to describe fully the physical counterpart of focal types of structural brain damage; at any rate, there has been relatively little concentration on efforts to explain the mechanisms that might