306 REPORT OF THE CHEMIST OF THE . 
albuminoids may be finally digested. The following shows a few 
of our results from redigestion with pepsin : 


PER CENT ALBUMINOIDS DIGESTED. 




rst Second Third 
digestion. | digestion. | digestion. 
Nyt YS 2h Pol CMT ee aa AR fa Oa tae aR av ee aR Oa EUR ek fay it he 79 84 29 
PEM OGMVADaV ee se ees ist ecideue aane ae ae mecca 59 29 34 
WHGBUDEAD tao e cheats meh clot cee hacire Men ane nase eee ets q7 23 | 11 



I can not say to what extent the digestibility might have been 
carried had the undigested residue been dried, reground and 
repeatedly digested, but each time to the third digestion showed 
a portion of the remaining albuminoids in each case to be digested. 
Stutzer, Jordan, Kellner, Pfeiffer and others have concluded 
from their investigations that by subjecting the feeces to artificial | 
digestion and taking the remaining portion as the undigested 
residue we have the digested portion of the food. There is no 
proof, so far as I am aware, to show that pepsin digestion of the 
feeces does not digest a portion of the food which was undigested 
by the animal. That it does do this seems probable from the fact 
that redigesting the feeces a second time gave another portion 
digested, as is shown below: 

PER CENT DIGESTED. 



No. 1. No. 2. 
BUTS HAIR ESLION isd oc Polen ck Rotate ees NEEL ee cle ean te ae en eee a 18.13 Do 1310 
Hecond digestions! ss us7a Ta, Cee. A us Sh ee ae 8.36 7.18 


If we assume that the amount actually digested by the cow is 
the apparent amount digested plus that portion of the feces 
digested by a pepsin solution, then instead of the digestion coeffi- 
cient for the albuminoids of orchard-grass hay being 60 per cent, 
it is nearly 68 per cent, or, if we take the amount redigested, it will 
be considerably increased over the last figures. 
In the light of our present data we conclude: 
1. That pepsin digestion furnishes us a reliable means of deter- 
mining the digestibility of the albuminoids of our feeding stuffs, 
thus serving as a criterion of the digestibility of the fodder itself. 
