a PHILOSOPHICAL TRANSACTIONS. [aNNO 1 683-4. 



ments, which shall pass into its cavity, so long, that they are sufficiently 

 drained, baked, hardened, or of a due consistence, as clay is tempered for the 

 mould, to receive the figure to be given it from the colon and rectum. This 

 use of the caecum, seems to me to be much more manifest in such animals as 

 have figured excrements of the first kind. In rats, whose excrements are con- 

 stantly alike figured, the caecum is very large, more capacious than the sto- 

 mach itself. But its use in receiving the excrements or exhausted chyle is not 

 more apparent from its large capacity, than that of farther drawing and tem- 

 pering them to a stiffiiess, for the service of the colon, from the admirable 

 contrivance and structure of this latter gut; it is to be noted, that immediately 

 under the valve of that gut in this animal are certain spiral fibres, which make 

 a kind of screw; now it seems to me, that the excrements, after they are 

 brought to a due consistence, by the necessary stay they make in the caecum, 

 and being carried out thence into the spiral foldings or screw of the colon, 

 cannot descend in a perpendicular, as formerly, through the small guts, but 

 still gently glide, and that very leisurely by the winding of the screw; whence 

 arises the figure. 



And I am apt to believe, that if the caecum of a rat, or any of the first kind 

 of animals mentioned, was tied up, or otherwise hindered from its receipt, the 

 animals would unavoidably fall into a diarrhoea, there being no reason why the 

 yet liquid excrements or exhausted chyle, such as we constantly find it, even 

 at the very bottom of the small gut, should stop at the entrance of the colon, 

 and not speedily glide through the screw, in a downright descent, that is, elude 

 the device of nature, and make the configuration of that so curiously contrived 

 part useless; we, I say, supposing the experiment to have taken away the ne- 

 cessary diverticulum and repository of the unprepared excrements in tying up 

 the caecum. 



I know not whether the observation will hold good in general terms, be- 

 cause, I say, I have not yet purposely examined divers animals in nature, viz. 

 that wherever there are elegantly figured excrements of the first kind, there is 

 ever a capacious caecum ; and on the contrary the less accurately figured and 

 more liquid the excrements of any animals are, the less the caecum, or none 

 at all. This is certainly true, that some animals, which are naturally loose, 

 have no caecum at all, or very little, as the talpa, the echinus terrestris, the 

 gulo; and, amongst the birds, the woodpecker kind, the hawk kind, &c. 



We forbear to offer any doubts concerning nature's end, in the necessary 

 figuration of the excrements in some animals, as first to prevent diarrhoeas; se- 

 condly to abide hunger the better; thus snails in the winter rest with full intes- 

 tines; thirdly, and chiefly to heighten the fermentation and digestion in the 



