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IOWA ACADEMY OF SCIENCE Voi.. XXVIII, 1921 
of each of the elements present in that particular quantity— just 
enpugh of calcium, for instance, not too much nor too little, be- 
cause if there is too much that may sometimes put a burden upon 
the animal organism, and if there is too little the inadequacy is 
' evident. 
Fifth — There should he present fat soluble A in large enough 
quantity to meet the demands of the organism — fat soluble A such 
as is found in butter fat, carrots, alfalfa leaves, meat meal tank- 
age, the lighter fractions of beef fat, and the other vitamines, and 
so on. 
Sixth.—W ater soluble B and the other vitamines should not be 
neglected. They are necessary — fortunately the water soluble B 
is quite widely distributed. There is some question about the anti- 
scorbutic being absolutely essential. 
Seventh — The fibre content should be relatively low. Too much 
fibre is a detriment to young, growing pigs. 
Eighth — There should be an abundance of starch or equiva- 
lent in sugars or similar materials to furnish the energy and fat- 
tening requirements of the organism. 
Ninth — Toxic materials should not be contained within the ra- 
tion, in other words all of the ingredients should be healthful and 
not of toxic or poisonous character. 
Tenth — Other considerations general in character should be 
given attention — such considerations as palatability, laxativeness, 
high digestibility, relatively high net production value, and the 
correct relationship between all of the various constituents, their 
relationship changing as the demands change — in other words as 
the animal grows and develops. 
It can be readily seen that in considering the complete nutrition 
of an animal the problems arising therefrom are many and com- 
plex. The good ration can be made inadequate by the removal 
therefrom of a single nutritional essential such as fat soluble A 
or water soluble B, or certain amino acids, just as an automobile 
engine that is functioning properly can be totally incapacitated by 
the removal of the timing gear, or the piston rings, or the spark 
plugs, or the gasoline, or the oil, and so on. Sometimes just a 
small quantity of a certain material like fat soluble A will gave 
results wholly out of proportion to its weight. The inflammable 
head of a match is very small but it can bring about wonderful 
changes under proper conditions. A catalyzer is very small in 
quantity but will cause changes which as compared to the cat- 
alyzer itself are of exceptional magnitude. 
