MECHANICAL PHENOMENA. 1? 



that those foods which delay the appearance of free hydro- 

 chloric acid in the stomach remain longest in this organ. 

 More recently CANNON l has rein vestiga ted this subject, 

 confirmed the findings of PENZOLDT, and outlined a theory 

 of the action of the pylorus which agrees with experimental 

 and clinical facts as we know them to-day. 



CANNON investigated the rate at which different food- 

 stuffs leave the stomach to enter the small intestine. As 

 examples of a nearly pure protein diet, boiled beef free from 

 fat, boiled whitefish or the white meat of fowls was used. 

 Beef-suet, mutton-f^fcpr pork-fat served as nearly pure 

 fats, while starch psMe, rice, and potatoes were taken as 

 examples of a carbohydrate diet. Definite amounts of the 

 various foods mixed with bismuth subnitrate were fed 

 to full-grown cats which had been without food for twenty- 

 four hours previously, and by means of the x-ray the 

 rapidity was noted with which the various foodstuffs escape 

 into the intestine. The time at which the food begins to 

 move into the duodenum can be accurately determined in 

 this way, and by measuring the aggregate length of the 

 shadows in the small intestine at half-hour or hourly in- 

 tervals the relative amounts of food in the intestine from 

 time to time can be fairly well gauged. 



In the following curves (Fig. 3) constructed from CAN- 

 NON'S figures are indicated the different velocities with 

 which protein, fat, and ^fbohydrate leave the stomach. 

 It will be seen that theP^fs and carbohydrates begin to 

 move out of the stomach soon after ingestion, the carbo- 

 hydrates leaving very rapidly, while the fats leave only 

 slowly. The curve representing the carbohydrates, (curve C) 

 ris6s rapidly to a maximum which is reached at the end 

 of the second hour, to fall more slowly after this point is 

 passed. The curve for fats (curve A} both rises and falls 

 slowly, does not reach its maximum until the third hour, 



1 CANNON: Journal of the Am. Med. Assoc., 1905, XLIV, p. 15. 



