136 RUMINATION. 



swallowed food is, therefore, speedily mixed with the portion 

 which must necessarily lodge, however long an animal may 

 fast, in the lower pouches of the rumen, notwithstanding 

 the most perfect digestion. 



It is evident, that prolonged maceration in the paunch will 

 reduce food to a pulpy mass, facilitating the trituration and 

 after- solution by the digestive fluids. All soluble materials 

 which the saliva and other fluids swallowed may dissolve, are 

 rendered fit for passage onwards in the alimentary canal; 

 and however feeble the action of the diluted secretions above 

 referred to, nevertheless it must aid in the changes to be 

 effected on the starchy principles which the food of rumi- 

 nants so largely contains. Flesh, on the other hand, yields 

 its soluble principles, and undergoes a kind of digestion in 

 the rumen, as Colin has proved. 



The precise nature of the action is involved in some mys- 

 tery. It is regarded as a fermentation; but this process is 

 most marked in cases of disease, when an abundant evolution 

 of gas indicates a dangerous and rapid chemical change in 

 the contents of the paunch, which may soon prove fatal to 

 the animal. At all times, however, a certain amount of gas 

 is disengaged from the food. 



The infusion and solution of substances occurring is in- 

 dicated by Tiedemann and Gmelin's analysis of the liquids 

 in the paunch. They found 



1. Free carbonic acid disengaged by heat. 



2. Sulphuretted hydrogen. 



3. Acetic acid. 



4. Butyric acid. 



5. Carbonate of ammonia. 



6. Acetate of ammonia. 



7. Butyrate of ammonia, 



8. Albumen. 



