FOODS — HI \1 W NUTRITION. 61 



and by passage into the large intestine. Consequently three is never any greal 

 accumulation of tat in tin- small intestine. 



"Carbohydrate foods begin to leave the stomach soon after their ingestion. The) 

 pass out rapidly, and at the <*ik I of 2 hours reach a maximum amount in the email 

 intestine almost twice the maximum for proteids, and two and a half times the max- 

 imum for fats, both of which maxima arc reached only at the end of l hours. The 

 carbohydrates remain in the stomach only aboul half as long as the proteids. 



"Proteids frequently do not leave the stomach at all during the first half hour. 

 After 2 hours they aeciin hi late in the small intestine to a degree only slightly greater 

 than that reached by carbohydrates an hour and a half earlier. The departure of 

 proteids from the Btomach is therefore slower at firsl than that of either fats or car- 

 bohydrates. An exception to this general statement was found in egg albumen, 

 which, both in its natural state and in coagulated form, was discharged from the 

 stomach at about the carbohydrate speed. 



"When carbohydrates are fed first and proteids second, the presence of proteids 

 in the cardiac end of the stomach does not materially check the departure of the 

 carbohydrate food lying at the pylorus; but the presence of proteids near the pylo- 

 rus, when proteids are fed first and carbohydrates second, markedly retard- the 

 onward passage of the carbohydrates which under these circumstances predominate 

 in the cardiac end of the stomach. 



" When carbohydrates and proteids are mixed in equal parts, the mixed food does 

 not leave the stomach so slowly as the proteids, nor so rapidly as the carbohydrates — 

 the discharge is intermediate in rapidity. 



"In a mixture of fats and proteids in equal parts, the presence of the fat causes the 

 proteid to leave the stomach even more slowly than the proteid by itself. Fat mixed 

 with carbohydrate in equal amounts also causes the carbohydrates to pass the pylorus 

 at a rate slower than their normal. 



" Doubling the amount of carbohydrate food (50 cc. instead o£25cc.) increases the 

 rapidity of the carbohydrate outgo from the stomach during the first L' hours; whereas 

 doubling the amount of proteid food strikingly delays the initial discharge of proteid 

 from the stomach. 



"The process of rhythmic segmentation is seen with all three kinds of f 1 stuffs. 



and the frequency of its occurrence corresponds roughly to the amount of f 1 present 



in the intestine: a measurement of the length of the segmenting masses in a given 

 number of cases shows that at the regular times of observation, during the first 7 

 hours after feeding, the amount of segmenting activity in the presence of carbo- 

 hydrates was much greater than in the presence of either fats or proteids. Egg 

 albumen is excepted in this genera] statement. 



"The interval between the feeding and the appearance of food in the large intes- 

 tine is variable, but the mean for carbohydrates is about 4 hours, for proteids about 

 ti hours, and for fats about 5 hours. After time is allowed for the later start of pro- 

 teids from the stomach, there still remains a probability that the proteids pass 

 through the small intestine more slowly than do the carbohydrates." 



Changes in the excretion of carbon dioxid resulting from bicycling, (J. < >. 

 Hk.i.kv and W. 1'. Bowen [Ann,-. Jour. Physiol., I .' i 1904), No. 7, pp. 811-885, fig*. 

 7). — A respiratory mask of special construction is described which fits tightly over 

 the nose and month and contains valves for the separation of the inspired and 

 respired air current 



The respired air is dried by passing through tubes tilled with pumice stone ami 

 sulphuric acid and then through a L r as meter, which is connected with the suction 



side of a blower, in order to relieve the lungs of the subject from the labor involved 

 in forcing the expired air through the tubes and gas meter. The dry air containing 

 carbon dioxid passes through an absorption apparatus attached to one arm of a 

 counterpoised balance. As the arm sinks, owing to the absorption of carbon dioxid, 



