On Intestinal Rest and Movement. 



227 



evident after a few experiments had been made with each. The 

 introdnction of the larger metal sound (9 X 14 mm.) was usually 

 followed by a well-marked peristalsis occurring immediately after- 

 wards (Experiment III), lasting for 1' to 3', and propelling the 

 sound 2 to 5 cm. into the fistula of the fasting animal. With the cork 

 sound of equal size, but lesser weight, the effect was the same ; with 

 the narrow capsule (6 X 14 mm.) and the meat fragment, this primary 

 peristalsis of introduction was much less marked. After the period 

 'of activity had passed, the time occupied in the transit through the 

 entire length of the fistula appeared to be closely similar in the 

 larger and smaller bodies ; in other words, those of greater size which 

 at first excited motion soon ceased to do so, the intestine becoming 

 "accustomed" — as the oesophagus does — to their presence. 



When a phase of activity is present, as during the time imme- 

 diately succeeding the introduction of food into the stomach, all 

 evidence that larger bodies contribute by their size to a more rapid 

 propulsion through the fistula, is lost. (If there were greater varia- 

 tion in the diameter of the sounds employed than existed in those 

 used in these experiments, it is possible that some slight exceptions to 

 this statement might be found.) 



Changes in Character of Peristaltic Contractions. 



It is not my purpose at the present time to enter into a minute 

 examination of the character of individual peristaltic contractions 

 occurring under various circumstances, although I have alluded to 

 this question very briefly on page 214. As, however, the consideration 

 of peristalsis, stimulated by the introduction of a large sound into the 

 fistula, has been brought under notice, I can scarcely omit contrasting 

 the nature of the waves produced in this manner (and which are very 

 similar to those occurring in all portions of the fasting intestine), and 

 the digestive peristalsis occurring in the same animal half an hour 

 after a full meal. 



It is found on registering them upon a cylinder having a medium 

 velocity, that the contractions occurring in the first (fasting) condition 

 are much more numerous in a given time, frequently nearly twice as 

 many as in the latter ; that the individual contractions have a shorter 

 maximum which is attained more quickly, and that their relaxation is 

 more abrupt and complete. As a result we find that in spite of the 

 greater number of contractions the sound advances further in the 

 same time after food than it did when food had not been recently 

 administered. Some hours after the meal the change is even more 

 striking, long periods of rest occurring which are from time to time 

 broken by a few faint contractions, having a sustained maximum and 

 an imperfect relaxation. 



