10 
ALFALFA—ITS GROWTH, DIGESTIBILITY, ETC. 
bath at 100° C. until the weight is constant—the loss is 
water. A refinement of this method is to dry the sample 
in a stream of hydrogen gas until no further loss occurs. 
Ash —Ash is what is left after the combustible matters 
of the analysis in question are burned away, at a low red 
heat; there is usually a little charcoal and also some sand 
that has been washed or blown upon the plants ; these are 
sometimes called accidental inpurities. 
Fat, or Crude Fat —Includes everything which can be 
extracted from the feeding stuff by absolute ether; in this 
list is commonly included chlorophyll (the green coloring 
matter of plants) fat, wax and fat oil. 
Albuminoid Nitrogen ( Protein )—This includes all those 
nitrogenous substances which resemble white of egg, flesh, 
fibrin, milk casein (curd). The amount of nitrogen found 
is multiplied by 6.25 ; this number is based upon the fact 
that albuminoids contain about 16 per cent of pure nitro¬ 
gen ; this is but an approximation, but it is sufficiently ac¬ 
curate for practical purposes and is the number generally 
agreed upon; it is well known that nitrogen is found 
in other combinations than albuminoids, viz., in 
amides, alkaloids, nitrates, etc., but in these it. is usually 
in small proportion, and does not materially influence 
the result. 
Crude Fiber , or Cellulose —Is the essential part of the 
walls of vegetable cells. It is in quite a pure state in cotton 
fiber; it is quite insoluble, and remains as a residue when 
the feeding stuff' lias been treated with acid and alkali. 
There is another constituent called carbohydrate or 
nitrogen free extract, and it includes such bodies as gum, 
starch, sugar, etc. These are extracted by water or 
dilute acids, but they are always indirectly determined 
by subtracting the sum of ash, fat, albuminoids and 
crude fiber from the total dry matter. 
We are now prepared to consider the table containing 
the results of the analyses of alfalfa, clover, grass and 
wheat bran conducted in the Colorado Experiment Station 
laboratoiy : 
