SECT. XXXVII. 3. i. SECRETION, &c. 363 



inflamed ; it follows, that thole were, when firft formed, ap- 

 pendages to the nerves of fenfation or locomotion, or were 

 formed from them. And that hence all thefe folid parts of the 

 body, as they have originally confided of extremities of nerves, 

 require an appofition of nutritive particles of a fimilar kind, 

 contrary to the opinion of BufTon and Needham above recited. 



Laftly, as all thefe filaments have poflefled, or do poflefs, the 

 power of contraction, and of confequent inertion or elongation ; 

 it feems probable, that the nutritive particles are applied during 

 their times of elongation ; when their original condiment par- 

 ticles are removed to a greater diftance from each other. For 

 each mufcular or fenfual fibre may be confidered as a row or 

 firing of beads ; which approach, when in contraction, and re- 

 cede during its reft or elongation \ and our daily experience 

 {hews us, that great action emaciates the fydem, and that it is 

 repaired during reft. 



Something like this is feen out of the body ; for if a hair, or 

 a fingle untwided fibre of flax or filk, be foaked in water ; it be- 

 comes longer and thicker by the water, which is abforbed into. 

 its pores. Now if a hair could be fuppofed to be thus rmmerfed. 

 in a folution of particles fimilar to thofe, which compofe it ; 

 one may imagine, that it might be thus increafed in weight and 

 magnitude ; as the particles of oak-bark increafe the fubdance 

 of the hides of beads in the procefs of making leather. I men- 

 tion thefe not as philofophic analogies, but as fimilies to facili- 

 tate our ideas, how an accretion of parts may be effected by 

 animal appetences, or feleclions, in a manner fomewhat fimilar 

 to mechanical or chemical attractions. 



If thole new particles of matter, previoufly prepared by di- 

 geftion and fanguification, only fupply the places of thofe, which 

 have been abraded by the actions of the fydem, it is properly* 

 termed nutrition. If they are applied to the extremities of the 

 nervous fibrils, or in fuch quantity as to increafe the length or 

 crafhtude of them, the body becomes at the fame time enlarged, 

 and its growth is increafed, as well as its deficiencies repaired, 



In this lad cafe fomething more than a fimple appofition or 

 felection of particles feems to be neceflary ; as many parts of 

 the fydem during its growth are caufed to recede from thofe, 

 with which they were before in contact ; as the ends of the 

 bones, or cartilages, recede from each other, as their growth 

 advances : this procefs refembles inflammation, as appears in 

 ophthalmy, or in the production of new flefh in ulcers, where 

 old veffcls are enlarged, and new ones produced ; and like that 

 is attended with fenfation. In this fituation the veflels become 

 didended with blood, and acquire greater fenfibility, and may 



thus 



