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with the fact just mentioned, that the life of this side of the heart 

 is not maintained by the blood in the ventricle, &c.; and although 

 arterial blood passes through the left cavities of the heart, it is to 

 be inferred, from the resemblance of their structure to that of the 

 right side, that there is another source of the elements of life besides 

 the blood in the ventricles: in other words, that the blood from 

 which the life of the heart is assimilated is not that which is con- 

 tained hi the ventricles, but that which circulates in vessels of another 

 order. It will be suggested that the conclusion is further supported 

 by the fact, that, in asphyxia, the circulation is continued a short 

 time after the office of the lungs is prevented. The evidence how- 

 ever of this fact appears to lose its force when we recollect that the 

 action of the heart will continue for a time, when the circulation 

 (an acknowledged source of its permanent life and action) has ceased. 



14. There are no facts which prove that the pabulum of the 

 structural assimilation of the heart is furnished by the blood in its 

 cavities. The argument of analogy, quoted in the last paragraph, 

 would rather decide against such a supposition ; for, if venous blood 

 will not maintain spiritual assimilation, we can scarcely expect that 

 it should produce the structures, the formation of which we know 

 to be dependent upon the life which precedes their growth and 

 preserves their cohesion. 



15. To repeat: the two questions proposed, as including the 

 physiology of the life of I he heart, and the relation between this 

 organ, and the blood in its cavities, are, 1st, Are the assimilating 

 and functional properties of the heart identical or distinct? 2nd, 

 What are the relations of the blood with the above properties? 



1G. These questions, agreeably with our discussion, are thus 

 answered: 1st, There is an entire absence of proofs whether the 

 heart is directly dependent upon a related seat for the properties 

 which aid or perform its motions. The action of the heart may be 

 influenced, as every one knnws, by affections originating with distant 

 nerves: but this fact proves no regular dependence. 2nd, There are 

 no facts which prove either that the functional or common spiritual 

 properties of the heart are renewed from the blood in its cavities. 

 At the same time there is reason to believe that the action of the 

 heart may be affected by the quantity of the blood in its ventricles, 

 &c.: this will be supposed in agreement with many analogies. We 

 are, in this case, precluded the analytical test of dependence, because 

 the blood cannot be excluded the ventricles without a cessation of 

 the circulation; and any inference which might be made from the 

 observation of phenomena under such circumstances would be 

 equally, and perhaps more justly, attributed to the absence of blood 

 in the coronary arteries. 



17. The strongest facts which relate to the physiology of the 

 heart are, 1st, the heart continues to act after a division of its 

 nerves: this fact suggests the conclusion that the action of the heart 

 is independent of a nervous centre. 2nd, The heart is paralyzed by 

 tying the coronary arteries: this fact suggests that the life and 



