136 



renewed in the course of a few days : and all this latter process from 

 no olher imputed source than what a man eats and drinks, which is 

 not a little wonderful, considering that it is not the custom for men 

 to eat their own weight of food in five or six days, to say nothing 

 about those considerable portions of it which are known to be 

 excrementitious. 



25. With regard to the second proof, viz. that bones, &c. will 

 disappear under disease, this might be accomplished without any 

 vessels distinct from those which are continuous with the arterial 

 system; for by disease the life of a bone, &c. may be destroyed to 

 a certain extent, and its particles, being comminuted and their union 

 dissolved, may be received into and propagated along vessels whose 

 extremities are patent from a partial destruction. Without insisting 

 upon this matter, as I do not mean to question the existence of 

 absorbent vessels, it is sufficient to remark, that though a part may 

 be absorbed under a state of disease, or though an absorption of 

 the fluids, extravasated into the cavities, may be perpetually going 

 on, we are not therefore to infer that the absorption of the solid 

 particles, those which are impacted and coherent, is unremitting in 

 health. Is there then, I would ask, any proof that the particles now 

 identically constituting the solid fabrics of the body, do not remain 

 or preserve their places as long as life lasts, unless disturbed by pro- 

 cesses of disease? 



2G. To this question it may perhaps be replied, the incessant 

 attrition between the fluids and the solids in the work of circulation 

 roust necessarily produce the decomposition of the solid panicles. 

 If this is necessary, then there is no more to be said about it; but 

 that it is necessary, I am inclined to question on the following 

 grounds: 



27. 1st, That our experience of the effects of attrition, in 

 decomposing solid particles, is only among such as cohere by a com- 

 mon property of matter; whereas, in the animal structures the bond 

 of union is of a different kind, it is by the force of the organic spirit, 

 which we know to be so far efficient, that it resists the chymical 

 tendency to decomposition, which, as it prevails after death in a 

 shorter time than that in which a mechanical agency, as by tire 

 attrition of the fluids, would accomplish the same total waste; we 

 must on this account conceive the spiritual power of aggregation to 

 be equal to counteract the weaker, if it is sufficient to counteract 

 the stronger, tendency. The case is different in disease, where the 

 bond of union is perhaps the first to be affected, and then follows, 

 very naturally, such a change in the cohesion of the textures as is 

 agreeable with the change of the medium which unites them. 



*28. 2nd, That the power of mere attrition is not sufficient to 

 decompose the solid particles seems to be further indicated by the 

 following consideration, viz. during the periods of growth solid par- 

 ticles are actually laid down and cohere with the rest; now these 

 particles existed in that fluid which afterwards performs the attrition 

 upon them. If the affinity which aggregates these particles is 



