32 CORA SENNER WINKIN 



obtained. The average level between occlusions was relatively high, 

 pressure seldom falling below 60 mm. Hg. 



The first four or five occlusions obtained differed in no very striking 

 detail from control occlusions. The main change from the type of 

 these earlier occlusions appeared gradually. This was a slight delay 

 in the appearance of the first rise in pressure and a gradual increase in 

 the magnitude of this first effect. The fall of pressure from this first 

 level also became more pronounced; pressure dropped to increasingly 

 lower levels at this time on successive occlusions. By the time of the 

 seventh or ninth occlusion the emphasis on this first part of the curve 

 became so well marked that the entire response appeared more as two 

 separate curves rather than one, the two summits in the tracing being 

 very symmetrically distributed both in time and space. The fall of 

 pressure following the initial rise was so great in some of the animals 

 as to approach the base line very closely, dropping to a level of only 

 10 to 20 mm. Hg. 



The characteristic new contour of the rise, once established, is re- 

 tained in all subsequent tracings in the same animal with great uni- 

 formity (fig. 5B). The latter part of the series of occlusion records 

 accordingly shows this new type of anemic rise. The marked drop in 

 the double curve is quite different from the dip due to vagus action 

 seen in the ordinary control pressure curve of anemia. It comes much 

 later (fig. 4); it is also decidedly more abrupt and greater. In fact, 

 it seems much more like an actual collapse of blood pressure. It appears 

 uncomplicated by slowing of the heart. The very definite time rela- 

 tions established in these dissociated curves are striking. Indeed, the 

 supplementary rise, once it has become separated from the initial rise 

 by the marked temporary collapse of blood pressure, is recorded at 

 exactly the same point in all later occlusions obtained in a given animal. 

 This time closely approximates half of the occlusion time of the animal 

 in which it appears, namely, at 1 minute in cats of 2-minute occlusions, 

 and so forth. A decrease of the anemic increment was obtained in the 

 course of the repetitions. Rises of 80 to 100 mm. gradually replaced 

 the original increment of 120 to 140 mm. 



One further observation on these cats is worth noting. Post-mor- 

 tem examination showed that the blood of these animals failed to clot 

 readily. It frequently flowed freely from the carotid artery when the 

 cannula was removed. In a prolonged dissection in one animal, the 

 blood flowed freely from every rupture of a large vessel, even as late 

 as one hour after death. 



