EXCKETIONS 509 



utilization of carbohydrate has generally been given as about 98 per cent, 

 it is evident from these figures that on a diet of 300 to 400 grains carbo- 

 hydrate it is above 99 per cent. As Langworthy and Deuel have recently 

 pointed out, contrary to the general assumption, even raw starch may be 

 quite well utilized. Ordinarily starch digestion does not seem to be inter- 

 fered with, though the amount of carbohydrate eliminated in the severer 

 catarrhal conditions of the intestine may be slightly increased. One, 

 question to be asked with regard to all carbohydrate material is, are the 

 enzymes of the alimentary canal capable of hydrolyzing it ? As Mendel 

 and certain of his pupils have pointed out, there appear to be no enzymes 

 in the digestive tract capable of attacking certain of the more complex car- 

 bohydrates, such as agar agar, Iceland moss, inulin, certain galactans, etc. 



Ash. The inorganic constituents of the feces are derived partly from 

 the intestinal secretions and partly from the food. The proportion which 

 comes from the food varies with the nature of the diet. A purely meat 

 diet results in a lowering of the ash content, of the feces, while with a 

 milk diet the ash is increased, owing to the presence of unabsorbed lime. 

 On an ordinary mixed diet the ash of the feces generally falls between 

 10 and 15 per cent of the dry weight, but on a milk diet values of 25 to 

 35 per cent are found, about 40 per cent of which is due to calcium. 

 Pathologically, Cammidge has occasionally observed cases of chronic 

 colitis in which as much as 45 to 50 per cent of the dry weight of the 

 feces consisted of inorganic ash. 



A general idea of the composition of human feces may be obtained 

 from the table on the next page taken from Myers and Fine, giving the 

 fecal analyses of a series of pellagra patients. Except for Case 5 (a male) 

 the patients were all rather small women. It is not believed that the 

 findings differ very materially from what would be found in other hospital 

 cases on similar diets, and with similar fecal movements. The cases have 

 'been divided into two groups, the first group having well formed stools, 

 and the second group soft or diarrheal stools. The diet in all cases was 

 lacto vegetarian, which probably explains the rather high ash figures ob- 

 tained. Estimations of iron and sodium were not made. The figures 

 recorded in the literature for the daily excretion of .sodium (as Na 2 O) 

 in the feces amount to 0.25 to 0.35 gram, and for iron (as FeO) 

 to 25 to 40 mg. (The daily excretion of iron in the urine varies from 

 1 to 5 mg.) An idea of the comparative importance of the intestines 

 and kidneys as paths for the elimination of various elements may be 

 obtained from the table on page 511. The figures are computed from the 

 previous table and urinary data for the same period. 



An inspection of the table shows that in the first group of cases the 

 total nitrogen and total sulphur parallel each other very closely, as prob- 

 ably might be expected from their common origin (protein). With diar- 

 rhea, sulphur does not appear to be quite as well absorbed as the nitrogen. 



