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ascend along their transverse processes. The same effect, viz. the speedy 

 death of the animal is produced by tying the ascending aorta in an herbi- 

 vorous quadruped. 



These experiments, which have been repeated a number of times, de- 

 cidedly prove the necessity of the action of the heart on the brain, in pre- 

 serving life. But how does this action operate ? Is it merely mechanical? 

 Does it consist solely in the gentle pressure which the arteries of the 

 brain exert on the substance oif this viscus, or is it merely, to the inter- 

 cepted arterial blood which the contractions of the heart determine to- 

 wards the brain, that death is to be attributed ? The latter opinion seems 

 to me the most probable, for, if, the moment the vertebrals have been 

 tied, the carotids are laid open, and the pipe of a syringe adapted to them, 

 and any fluid whatever is then injected with a moderate degree of force, 

 and at nearlv the s*ame intervals as those of the circulation, the animal 

 will not be restored to life. 



The heart and brain are, therefore, united to each other by the strict- 

 est connexion, the continual access of the blood flowing along the ar- 

 teries of the head, is, therefore, absolutely necessary to the preserva- 

 tion of life ; if intercepted, for one moment, the animal is infallibly de- 

 stroyed. 



The energy of the brain appears, in general, to bear a relation to the 

 quantity of arterial blood which it receives. I know a literary man, who, 

 in the ardour of composition, exhibits all the symptoms of a kind of brain 

 fever. His face becomes red and animated, his eyes sparkling ; the ca- 

 rotids pulsate violently ; the jugular veins are swollen, every thing indi- 

 cates that the blood is carried to the brain with an impetus, and in a 

 quantity proportioned to its degree of excitement. It is, indeed, only du- 

 ring this kind of erection of the cerebral organ, that his ideas flow with- 

 out effort, and that his fruitful imagination traces, at pleasure, the most 

 beautiful descriptions. Nothing is so favourable to this condition as re- 

 maining long in a recumbent posture : in this horizontal posture, the de- 

 termination of the fluids towards the head is the more easy, as the limbs, 

 which are perfectly quiescent, do not divert its course. He can bring on 

 this state by fixing his attention steadfastly on one object. May not the 

 brain, which is the seat of the intellectual action, be considered as a cen- 

 tre of fluxion ; and may not the stimulus of the mind be compared, as to 

 its effects, to any other stimulus, chemical or mechanical* ? 



A young man of a sanguineous temperament, subject to inflammatory fe- 

 vers which always terminate by a profuse bleeding at the nose, experien- 

 ces, during the febrile paroxysms, a remarkable increase of his intellec- 

 tual powers and of the activity of his imagination. Authors had already 

 observed, that in certain febrile affections, patients of very ordinary pow- 

 ers of mind, would sometimes rise to ideas, which in a state of health, 

 would have exceeded the limits of their conception. May we not ad- 

 duce these facts in opposition to the theory of a celebrated physician, 







* The inequality of the distribution of the blood, attributable to the peculiar action 

 of food &c. on the stomach and nerves, immediately connected with the great vessels 

 going to the brain, is peculiarly worthy of the attention of physiologists and pathologists. 

 In a paper, published in the 3d volume of the Philadelphia Journal, an attempt is mad6 

 "to show the relation of nerves producing 1 some of the most remarkable sympathetic 

 connexions. Godmav . 



