lie A MdiKKil of Veterinary Physiology. 



It is to Colin, Ellenberger, and Hofmeister that we owe 

 nearly all we know about the physical and chemical changes 

 occurring in the stomach, these observers having experi- 

 mented with different foods on a large number of animals 

 which were destroyed at certain intervals. Working on the 

 same lines, I have for many years carried on, as opportunity 

 occurred, observations of a similar nature. In this way a 

 large number of facts have been obtained, a summary oi 

 which can only be embodied in this chapter. 



The first peculiarity to be noticed in soliped digestion is 

 that the stomach is rarely empty ; no matter at what period 

 of digestion observations are made, food is still to be found 

 in it. It is only when horses have purposely been deprived 

 of nutriment for not less than twenty-four hours that an 

 empty stomach can be obtained. On the other hand, feed- 

 ing experiments show that very shortly after food arrives 

 in the stomach it commences to pass out, and the difficulty 

 thus presented to the observer in reconciling these opposite 

 facts is at first sight insuperable. 



It is perfectly true that food does pass out early, it is 

 equally true that it is long retained ; these opposite condi- 

 tions are the result of the periods of digestion. When food 

 enters an empty stomach it passes towards the pylorus, 

 where it meets with a fluid of an alkaline or neutral reac- 

 tion which has come from the mouth. As more food is 

 consumed some commences to pass out at the pylorus into 

 the bowel, the amount passing out not equalling at present 

 the amount passing in; the stomach becomes gradually dis- 

 tended, and when two-thirds full, which is the condition 

 in which the most active digestion occurs, the amount pass- 

 ing out will, if more food be taken, equal the amount being 

 swallowed, so that we have a stream of partially peptonized 

 chyme streaming out of the right extremity, while a cor- 

 responding bulk of ingesta is entering the inert Left sac. 

 In fact, the stomach may pass out during feeding two or 

 three times the bulk of food remaining in it when the feed 

 is finished. Let us suppose now that by this time the 

 'feed' is finished; at once the passage of chyme into the 



