180 NATURAL THEOLOGY, 



show, not only the contrivance, but the perfection 

 of it. We may remark, first, the length of the in- 

 testines, which, in the human subject, is six times 

 that of the body. Simply for a passage, these vo- 

 luminous bowels, this prolixity of gut, seems in 

 nowise necessary; but in order to allow time and 

 space for the successive extraction of the chyle 

 from the digestive 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 condu- 

 civeness. 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 which is effected by the joint action 

 of longitudinal and of spiral, or rather perhaps of 

 a great number of separate semicirculg.r fibres. 

 This curious action pushes forward the grosser 

 part of the aliment, at the same time that the 

 more subtile 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 denomi» 

 nate lacteals, or their mouths at least, should be 

 made as narrow as possible, in order to deny ad- 

 mission into the blood to any particle which is of 

 size enough to make a lodgement afterwards in the 

 small arteries, and thereby to obstruct the circu- 

 lation ; and it was also necessary that this ex- 



