CHEMICAL COMPOSITION. 365 
falfa and also of the loss of nutritive properties 
through exposure to the weather. We quote him 
from Bulletin 155: 
COMPOSITION OF ALFALFA HAY. 
Nitro- 
: Crude Pure Crude Crude 
Water.| Ash. protein. | protein. | fiber. arels fat. 
First stage, about ten per 
cent in bloom........ .. 8.77 | 9.54 16.88 13.56 29.38 34.01 1.42 
Second stage, about one- 
half in bloom............ TTL 9,49 15.88 12.63 31.44 34.23 1.25 
Third stage, full bloom....| 8.29 7.75 18.23 10.62 33.11 86.34 1.30 
As the*amounts of moisture present in a hay are variable and 
not a characteristic of the stage of maturity of the green plant, 
a calculation of the results to a water-free basis is often advan- 
tageous in making comparisons. Doing this for the three sam- 
ples of alfalfa hay we get the following: 
COMPOSITION OF ALFALFA HAY CALCULATED TO A WATER-FREE BASIS 
Nitro- 
Crude Pure Crude Crude 
Ash. = gen - free 
protein. | protein. fiber. extract. fat. 
First stage...........ee eens 10.45 18.50 14.86 32.20 27.29 1.56 
Second stage .. ae 10.28 17.21 14.18 85.37 34.00 1.05 
Third stage.......ssceecees 8.45 14,43 11.58 36.10 389.62 1.41 
Without going into the details of a discussion of the charac- 
teristics of the groups of feed principles named in these tables 
it may be useful to remind the reader of certain elementary 
facts. 
The ash of a feeding-stuff is the residue left after burning all 
combustible substances. For the most part this is derived from 
the soil, though it may contain carbon that was secured from 
the carhon-dioxid in the air. 
The crude protein embraces all organic compounds containing 
nitrogen and may even include some inorganic nitrogenous sub- 
stances. 
The pure protein is the crude protein minus certain nitrog- 
enous substances that are less complex than proteins proper, 
and possess a lower food-value. The proteins, by reason of the 
nitrogen, sulphur and phosphorus which they contain, are en- 
titled to greater esteem in a feed than are fats and carbohy- 
drates. ? 
The crude fiber consists of cellulose and substances more or 
