4 22 GENERATION. Sect. XXXIX. 8. 3. 



lowed into the flomach ; the mouths of the lacteal veflels be- 

 ing agreeably ttimulated pofTefs an appetency to abforb the par- 

 ticles of the digefting mafs •, which is in a fituation of under- 

 going chemical changes, and pofTefles at fome period of them 

 an aptitude to ftimulate, and to be united with the mouths of 

 the abforbent lafteals. 



But when thefe abforbed particles of inanimate matter have 

 been circulated in the blood, they feem gradually to obtain a 

 kind of vitality ; whence Mr. John Hunter, and I believe fome 

 antient philosophers, and the divine Mofes, aiTerted, that the 

 blood is alive ; that is, that it pofTefTes fome degree of organi- 

 zation, or other properties, different from thole of inanimate 

 matter ; which are not producible by any chemical procefs, and 

 which ceafe to exift along with the life of the animal. Hence 

 for the purpofe of nutrition there is reafon to fufpect, that two 

 circumftances are neceflary, both dependent upon life, and con- 

 fequent activity ; thefe are firft an appetency of the fibrils of 

 the fixed organization, which wants nutrition ; and fecondly a 

 propenlity of the fluid molecules exifting in the blood, or fe- 

 creted from it, to unite with the organ now ftimulated into ac- 

 tion. So that nutrition may be faid to be effected by the em- 

 brace or coalefcence of the fibrils, which pofTefs nutritive appe- 

 tencies, with the molecules, which pofTefs nutritive propenfities, 

 or in other words of particles, which pofTefs reciprocal appeten- 

 cies to embrace each other. 



8. If the philofopher, who thinks on this fubject, fhould not 

 be inclined to believe, that the whole of the blood is alive, he 

 cannot eaiily deny life to that part of it, which is fecreted by 

 the organs of generation, and conveys vitality to the new em- 

 bryon, which it produces. Hence though in the procefs of nu- 

 trition the activity of two kinds of fibrils or molecules may be 

 fufpected, yet in the procefs of the generation of a new vegeta- 

 ble or animal, there feems great reafon to believe, that both the 

 combining and combined particles are endued with vitality ; 

 that is, with fome degree of organization or other properties not 

 exifting in inanimate matter, which we beg leave to denom- 

 inate fibrils with formative appetencies, and molecules with 

 formative propenfities ; as the former may feem to pofTefs a 

 greater degree of organization than the latter. 



And thus it appears, that though nutrition may be conceived 

 to be produced by the animated fibrils of an organized part be- 

 ing fh.Tiulated into action by inanimate molecules, which they 

 'hen embrace ; and may thus be popularly compared to the 

 timple attractions of chemiliry ; yet that in the production of 

 ;: new einbryon, whether vegetable or animal, both the fibrils 



with 



