223 



tion, the pain occasioned by the division of the skin and of the nerves, 

 overcomes every other pain, and I have always seen patients impressed 

 with the popular prejudice, and expecting anxiously the division of the 

 bone, feel quite free from pain, as soon as the saw had begun to work. 

 Nay, several, after expressing, by their cries, the most acute pain, taking 

 advantage of the kind of ease which follows the division of the flesh, raise 

 their head, and look on, while the bone is being sawn through ; at once 

 actors and spectators in this last part of a painful and bloody operation. 



Yet the medullary membrane, the injury of which is attended with no 

 pain, while in a hea'lthy state, becomes the seat of the most exquisite sen- 

 sibility in the pains in the bones, which mark the last stages of the 

 venereal disease; in the kind of conversion into flesh, of the solid bone^ 

 known by the name of spina ventosa. as will be mentioned, in speaking 

 of the uses of the marrow, in the chapter on the organs of motion and 

 on theii* action. 



CHAPTER VI. 



OF NUTRITION. 



CVII. ALL the functions which we have hitherto made the object of 

 our study; digestion, by which the alimentary substances received with- 

 in the body, are deprived of their nutritive parts; absorption, which con- 

 veys that recrementitious extract into the mass of the fluids : the circu- 

 lation, by which it is carried to the parts wherein it is to undergo different 

 changes; digestion, circulation, absorption, respiration, and the secre- 

 tions, are but preliminary acts, preparatory to the more essential function 

 treated of in this chapter, and the consideration of which terminates the 

 history of the phenomena of assimilation. 



Nutrition may be considered as the complement of the functions of as- 

 similation. The aliment, altered in its qualities, by a series of decom- 

 positions, animalized and rendered similar to the substance of the being 

 which it is to nourish, is applied to the organs whose waste it is to 

 repair; and this indentification of the nutritive matter to our organs 

 which take it up and appropriate it to themselves, constitutes nutrition. 

 Thus, there is accomplished a real conversion of the aliment into our 

 own substance. 



There is incessantly going on a waste of the integrant particles of the 

 living body, which a multiplicity of circumstances tend to carry away 

 from it; several of its organs are constantly engaged in separating from 

 it the fluids containing the recrementitious materials of its substance 

 worn by the combined action of the air and of caloric, by inward friction, 

 and by a pulsatory motion that detaches its particles. 



Alike, therefore, to the vessel of the Argonauts, so often repaired in 

 the course of a long and perilous navigation, that on her return, no part 

 of her former materials remained: an animal is incessantly undergoing 



