EUMINAT10N. 135 



the rumen is then dispensed with, and it is therefore quite 

 rudimentary in the suckling animals. The reaction of the 

 contents of the first two stomachs is slightly alkaline. Tiede- 

 mann and Gmelin found it acid in calves, and Colin thinks 

 his experiments warrant him in declaring the reaction as 

 slightly acid when digestion is disturbed or suspended. It is 

 evident that this depends much on the changes occurring in 

 the food, because there is not sufficient secretion to give a 

 decided character to the mass contained, during digestion, in 

 the two first stomachs. Peyer, Bourgelat, Spallanzani, and 

 others, thought that the rumen secreted abundantly; but Colin 

 refers to the absence of a secreting structure as possessed by 

 the membrane lining this organ, which is papillated for the 

 production of an abundant protecting epithelium. Colin, 

 however, performed the following experiment, which proved 

 how insignificant in amount the secretion must be. He 

 opened the rumen and applied, against the membrane, a glass 

 capsule, containing a fine sponge, which he had previously 

 weighed. No sensible increase in the weight occurred by 

 allowing the sponge to remain in contact with the stomach 

 half an hour or an hour. 



The food lodged in the rumen and reticulum is subjected 

 to a slow churning movement, and not to the active grinding 

 or violent propulsive efforts which were once believed to aid 

 in the trituration and regurgitation of food. Fluorens 

 showed, that substances dropped into the posterior pouches 

 of the rumen rose, and were forced gradually forward into 

 the reticulum and back, without any very sensible contrac- 

 tions of the muscular walls of the viscera. By exposing the 

 interior of the paunch in a young bull, Colin noticed the 

 welling of the semi-fluid food, and the production of distinct 

 waves, with an ebbing flow, indicating the commotion set up 

 in every portion of the abundant contents. The newly 



