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LECTURE VI. 



ON SECRETION AND NUTRITION. 



At the conclusion of the former lecture, I 

 exhibited a kind of sketch of Mr. Hunter's 

 facts and opinions relative to the circulation 

 of the blood, and the change wrought in 

 that fluid, by respiration. I have now to en- 

 quire wherefore does the blood circulate? 

 Is it not for the nourishment of the body, 

 and the preparation of various fluids and 

 substances subservient to the animal eco- 

 nomy ? We believe, for reasons which I 

 need not detail on the present occasion, 

 these objects to be effected by means of 

 minute vessels, which go off from the ex- 

 treme arteries, and which sometimes ter- 

 minate by open orifices, effusing or deposit- 

 ing their contents ; whilst sometimes they 

 lead on to other channels, which collect 

 and convey the fluids they receive, to cer- 

 tain reservoirs or surfaces. These vessels 

 which prepare and separate something from 



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