386 BOARD OF AGRICUI.TDRE. 



It appoars that nuicb more of the nitro^^enous material is extracted 

 by pepsin digestion than l)y alcoiiol, ether and water. The later 

 solvents take out mainly the ])ile compounds. What tiiey fail to 

 remove is probably mucus, which is dissolved by the pepsin solution. 



''There is good reason for believing tiiat the feces contain con- 

 siderable mucus. Kellner* has made the observation that when the 

 excrement of sheep is dried the outer coating separates from the 

 nodules and rolls together in a tliin paper-like form. He concludes 

 that this outside layer is strongly impregnated with mucus. He 

 found that when the excrement is freed from these coatings it con- 

 tains a much smaller percentage of nitrogen than ))efore and that 

 the average amount of nitrogen thus removed was equivalent to .36 

 gr. for each 100 gr. of dry substance. Those who have conducted 

 digestion experiments cannot fail to have noticed that occasionally 

 strings of jelly-like matter are present in the feces, which must be 

 largely mucus."! 



It is plainly true that much of nitrogen in the feces does not 

 properly belong to the undigested residue of the food. It cannot at 

 present be shown that the pepsin solution extracts no more than 

 the nitrogen of this kind, but that it does so seems improbable. 



Comparison of arlijicial pepsin-x)ancreas digestion^ experiments with 

 animals, and the method proposed by Stutzer. These comparisons 

 are made b}' the use of data previously given under the bead of 

 ''Digestion Experiments" and those furnished by the last two tables. 

 This is done in the next table. In most cases the figures are the 

 average of two trials. 



*Bied. Centr. Agr. Chemie X, p. 157. 

 fFrom Agiicultural Science, Vol. I, p. 9. 



