188 PHYSIOLOGY CHAP. 



infrequent. These waves have a period of 35-55 sees. ; their 

 amplitude usually exceeds the excursion of the writing lever. 



When the sound is introduced into the pyloric antrum, a very 

 distinct form of rhythmical movement appears, consisting of 

 systoles and diastoles in regular succession, which are determined 

 by the total contraction or relaxation of the muscles of the antrum 

 (Fig. 63). Each revolution takes 10-30 sees., i.e. a shorter period 

 than each peristaltic wave. No other form of contraction due to 

 the tonic state of the walls is ever seen in the antrum, probably 

 because the circular fibres predominate so largely. 



The study of the conditions which produce these movements 

 of the stomach and their co-ordination with the several phases 

 of gastric digestion was very incomplete prior to Ducceschi's 

 observations. 



FIG. 63. Rhythmical systolic and diastolic movements obtained with introduction of sound into 

 pyloric antrum. (Ducceschi.) A, the lower tracing represents the respiratory rhythm. 

 B, time tracing marks 10 sec. 



According to some authors, the gastric movements after a meal 

 begin after a brief period of tonic contraction, i.e. shortly after the 

 ingestion of foods (Eberle, Blondlot, Brinton, Beaumont, Busch, 

 Kussmaul). Accerding to others, on the contrary, the meal is 

 followed by a period of tonic contraction lasting about an hour, 

 after which the movements set in with increasing intensity, 

 reaching their maximum after 3-4 hours (Magendie, Adelon, 

 Schiff, Leven). All, however, agree that liquid foods pass rapidly 

 through the pylorus into the duodenum a few minutes after 

 ingestion. The best observations have been made on man, or on 

 dogs with a duodenal fistula (Busch, Kiihne, Hirsch, v. Mering, 

 Moritz), which show that the contents of the stomach, particularly 

 the liquid parts, are spurted into the duodenum a few moments 

 after the meal. 



Leven (1902) specially investigated the time during which 

 fluids remain in the stomach. A measured quantity of water was 

 administered to dogs that had fasted for 24 hours; they were 



