186 



PHYSIOLOGY 



CHAP. 



movements exactly. According to his observations the fundus 

 and the pyloric antrum must be distinguished: the former has 

 mainly a digestive, the latter a motor function, as exhibited in 

 rhythmical contractions varying in number from 2-6 per minute. 

 Siuce the antrum fills in consequence of slight peristaltic waves 

 in the fundus, which are set up under very low pressure (2-6 cm. 

 water), the passage of the solid constituents of the gastric contents 

 into the duodenum is prevented. But the balloon which Moritz 

 introduced into the fundus is unable to transmit the peristaltic 

 movements as they succeed each other in the individual segments, 

 and minimises or cancels their effect on intra-gastric pressure. On 

 the other hand (given the relatively small size of the pyloric 

 antrum, and the almost synchronous systolic or diastolic move- 

 ments of its walls), it is obvious 

 that the elastic balloon can re- 

 cord considerable rhythmical 

 variations of pressure, up to a 

 maximum of 50 cm. of water. 



Ducceschi (1897) took up 

 this interesting question again 

 in Fano's laboratory, and pub- 

 lished an accurate account of 

 the excellent results he obtained, 

 which covered many lacunae and 

 conduced to a clear and satis- 

 FlG ^~h SCil Hf io 'V f >K nus inc d . ia f c P art J factory theory of the active 



stomach, i:obtamed with a sound introduced * J 



into dog by gastric fistula. (Ducceschi.) The movements Of the Stomach in 



lower tracing represents the respiratory move- -, , , j. ,. 



ments recorded by a Marey's pneumograph. relation to gastric digestion. 



His experiments were carried 



out on four large hounds previously provided with a gastric fistula. 

 This operation abolished the negative pressure which distends the 

 stomach ; its walls therefore tend to adhere, and a small balloon, 

 4-5 cm. in diameter, inserted between the two surfaces of the 

 abdominal walls, transmits the movements of the part of the 

 stomach in which it is placed to a tambour with tolerable 

 accuracy. 



The. animal is made to lie quietly on its side on a table (at 

 least 6 hours after a meal) and the cannula placed in the fistula 

 is opened; through this the sound fitted with the balloon is 

 introduced into the part of the stomach to be explored. Next the 

 balloon and sound are emptied of air by aspiration, and filled with 

 water, and then connected with a vertical glass cylinder, closed 

 above by a cork provided with two glass tubes, one long and 

 dipping into the water, the other short and communicating with 

 the column of air above the water. On joining the latter to a 

 Marey's tambour, the gastric curves are directly recorded, the 

 respiratory curves often being registered as well by a second 



