— 14 — 
After the digestion was completed, the alfalfa remaining 
was filtered off, washed free from chlorid, and the residual 
nitrogen determined by Kjeldahl’s method. 
The period of eight hours was decided upon, because we 
found in experimenting with the egg albumen that we ob- 
tained a complete solution in this time and seldom in a 
shorter period, and if we allowed it to stand longer a precipi- 
tate began to form which was not very readily gotten into 
solution again. This method contains an error in that it 
shows any soluble amids which may not be assimilated by 
the animal as digestible. As the amount of amids is quite 
large in some of the samples, this may give rise to compara- 
tively large errors. This error is not wholly eliminated in 
the case of animal digestion. The amount of amids had 
been previously determined in the samples of 1894 and 1895. 
They amounted to 10.85 per cent., for the first cutting, 19.93 
per cent., for the second cutting, and 5.03 percent, (one sam- 
ple only) for the third cutting. The amids were not deter- 
mined in the samples for 1896. The co-efficients of diges- 
tion obtained do not show any variation corresponding with 
the amids found. The sample of second cutting in half 
bloom shows a lower digestion co-efticient than the one fol- 
lowing it in full bloom, and still lower than the one preced- 
ing it in half bloom, and yet it contains amid nitrogen corre- 
sponding to 29.47 cent, of its crude protein. The others 
contained much less nitrogen in this form, the amount cor- 
responding to 18.84 percent., and 17.82 per cent, of the crude 
protein in the respective samples. 
The co-efficients of digestion for the proteids in alfalfa, 
as determined by animal digestion, are as follows : 
In green alfalfa, 78-83 ; mean of six trials, 81. 
Carefully dried alfalfa, 70-83 ; mean of six trials, 80. 
Alfalfa hay, early bloom, best quality, 71-83; mean of 
twenty-six trials, 76. 
Alfalfa hay, full bloom, 66-73 > nT^ean of ten trials, 68. 
Alfalfa ha34 carefully dried, 78; mean of two trials, 78. 
Alfalfa ha^^ as given in Colorado Bulletin No. 8, 77. 
Alfalfa hay as given by N. \\ Exp. Sta., 69. 
Considering these seven averages, we observe that five 
of them fall between 76 and Sr per cent. 
The only statements that I recall to have seen concern- 
ing the relative efficiency of animal and pepsin digestion is 
to the effect that the pepsin is rather higher, usually dis- 
solving from 2 to 6 per cent, more of the crude protein than 
is taken up by the animal. If we take the average of the 
five most nearl}' agreeing means, given above, we obtain 78.4 
