IIG NATURAL THEOLOaY. 



Here it meets the river — here it discharges itself into a large 

 vein, which soon conveys the chyle, now flowing along with 

 the old blood, to the heart. This whole route can be exhib- 

 ited to the eye ; nothing is left to be supplied by imagination 

 or conjecture. Now, besides the subserviency of this strdc- 

 ture, collectively considered, to a manifest and necessary pur- 

 pose, we may remark two or three separate particulars in it, 

 which show, not only the contrivance, but the perfection oi 

 it. We may remark, first, the length of the intestines, 

 which, in the human subject, is six times that of the body. 

 Simply for a passage, these voluminous bowels, this prolixity 

 of gat, seems in nowise necessary ; but in order to allow 

 time and space for the successive extraction of the chyle 

 from the digested aliment, namely, that the chyle which 

 escapes the lacteals of one part of the guts may be taken up 

 by those of some other part, the length of the canal is of 

 evident use and conduciveness. Secondly, we must also 

 remark their peristaltic motion, which is made up of contrac- 

 tions following one another like waves upon the surface of a 

 fluid, and not unlike what we observe in the body of an 

 earthworm crawling along the ground, and wdiich is effect- 

 ed by the joint action of longitudinal and of spiral, or rathe? 

 perhaps of a great number of separate semicircular fibres 

 This curious action pushes forward the grosser part of the 

 aliment, at the same time that the more subtle parts, which 

 we call chyle, are by a series of gentle compressions squeezed 

 into the narrow orifices of the lacteal veins. Thirdly, it 

 was necessary that these tubes, which we denominate lac- 

 teals, or their mouths at least, should be made as narrow as 

 possible, in order to deny admission into the blood to any 

 particle which is of size enough to make a lodgment after- 

 wards in the small arteries, and thereby to obstruct the cir- 

 culation ; and it was also necessary that this extreme tenu- 

 ity should be compensated by multitude ; for a large quan- 

 tity of chyle — in ordinary constitutions not less, it has been 

 computed, than two or three quarts in a day — is, by some 



