Sir E. Home on the Formation , &c, 147 



nine inches in length, and at the widest part three inches in 

 diameter : besides v/hich, both the colon and caeca have very 

 broad valvulas conniventes not met with in the casuary from 

 Java. This wonderful difference, for it is more than fifty to 

 one, can only be explained by the luxuriancy of Java being so 

 great, that this bird might destroy its health by over-feeding, 

 . had no guard been furnished by nature. 



This guard is, the food passing through the intestines with 

 so much facility, and in so short a time, that, however much 

 the bird may eat, only the necessary quantity of nourishment 

 is carried into the constitution ; but in the African ostrich, the 

 food is retained in the extensive colon till every thing nutri- 

 tious is extracted. In all ruminating animals, the colon is of 

 great length, is fixed in its course, which is very intricate, and 

 varies in every different genus ; so that we cannot doubt of 

 some particular process being carried on in it. 



The process which the contents of the colon undergo, is 

 quite distinct from any thing carried on in the other intestines, 

 since they entirely change their appearance and smell ; and 

 there is commonly a valve to prevent any part of them, even 

 the gases evolved, from being carried up into the small 

 intestines. 



The peculiar smell of the faeces, which borders so closely 

 on that from putrefaction, although by no means the samp, 

 led me to compare them with the animal matter buried in the 

 earth, which is converted into adipocere : in both cases the 

 substance is in the incipient state of putrefaction, but that 

 process never completely takes place ; it is excluded from the 

 external air, is either under water, or within the reach of im- 

 bibing moisture ; and there is no substance whatever, the chyle 



MDCCCXIII. X 



