APPETITE OP SWINE 
375 
IS THE APPETITE OF SWINE A RELIABLE INDICA- 
TION OP PHYSIOLOGICAL NEEDS ? 
JOHN M. EVVARD.i 
The pig is farrowed with a fairly definite set of specifications 
for development all wrapped np in their mystery in a two to 
three pound bundle of throbbing, active “stuff.” And yet be- 
fore the pig sought the outer life apart from the womb of his 
dam, these specifications were enclosed in the minutest bit of 
protoplasm, the impregnate ovum resulting from the union of 
two germ cells, one from the male and the other from the fe- 
male. 
These specifications may be likened unto the specifications for 
a house — the fulfillment is altered only upon provocation, and 
not then if avoidable. Certain materials are needed for this de- 
veloping piglet: water; proteins, really amino-acids, perhaps 
such as tryptophan, lysin, cystin, tyrosin, and many others; 
carbohydrates, probably of different sorts; fats of the effective 
kind ; minerals such as calcium, iron, magnesium, sodium, potas- 
sium, perhaps manganese, arsenic, and others; acid elements 
such as chlorine, sulphur, phosphorus ; vital substances, perhaps 
vitamines^ or “accessory diet factors”^ or “ akzessorische nahr- 
stoffe”^ ; and in reasonable probability other essential unknowns. 
There must not only be enough of these various nutrients at 
the right time in the alimentary tract, but likewise not an over- 
dose if optimum development is to be attained. Then too, the 
happy combination of these various factors in diet is a problem 
for the wisest of sages of all ages. 
Who will take the contract to figure out the bill of materials 
from the mostly unknown specifications? This has been at- 
tempted as will be shown shortly. 
That appetite is not to be depended upon in the formulation 
of rations is insisted upon by Jordan® who, in speaking of cattle, 
puts the proposition thus: “Once in a while some one talks 
^Acknowledgment is made for the collaboration and encouragement of Wil- 
liam H. Pew and Russell Dunn. 
2Funk, C. : Studien iiher das Wachstum, Ztschr. f., Physiol. Chem., 1913, 
LXXXVIII, 352. Also see Ergebn. d. Physiol., 1913, XIII, 124. 
^Hopkins, P. G. : Feeding Experiments Illustrating The Importance of Ac- 
cessory Factors in Normal Dietaries., Jour. Physiol., 1912, XLIV, 425. 
^A term suggested by Hofmeister. See also Oseki, S. : Biochein. Ztschr., 
1914, LXV, 160. 
^Jordan, Whitman Howard: The Feeding of Animals, 1906, p. 279. 
