T. B. Osborne and L. B. Mendel 435 
In the .ight of these facts we must admit that there are other factors 
than an adequate diet, which must be supplied to the growing chick, in 
order that it may complete its normal growth when under conditions such 
as are described.”’ 
Likewise Funk,? in referring to Drummond’s conclusion, that 
even chickens on normal diet do not thrive when kept under 
laboratory conditions, wrote: 
“This fact, of which I am fully aware, has been already emphasized in 
one of our publications. . . . . Still it also remains a fact that as a 
result of an inquiry into conditions existing in poultry farms, we are using 
now a mixture of chicken food, cabbage, and charcoal, the water being 
entirely replaced by milk, thereby succeeding in diminishing the mortality 
to a very great extent, in spite of the fact that the birds are kept in 
small cages.”’ 
The experience which we’ reported in feeding young chicks on 
selected rations encouraged us to make further attempts to as- 
certain the conditions under which these birds can be used, if 
possible, in the laboratory for the study of the factors essential 
for their nutrition during growth. Two of the chickens, Nos. 
5 o& and 6 o, reported in our earlier paper at the age of 81 
days, subsequently attained maximum body weights of over 6 
pounds—2,760 and 2,915 gm. respectively at the age of 309. 
days. Their plumage was well developed, their appearance ex- 
cellent, and both proved fertile. During a period of almost a 
year they were kept in cages not over 2x 2x 2 feet, were never 
removed from the laboratory, and never received any green 
fodder. Photographs taken at the age of 322 days are appended. 
During the period of these experiments the protein concen- 
trates fed were corn gluten, cottonseed flour, soy bean flour, and 
casein. “Protein-free milk’’ and butter fat were used as sources 
of “‘vitamines.’’ Starch, lard, and ferric citrate also entered into 
the diet. An abundance of water and grit was always furnished. 
Since these rations contained no roughage we early trained 
these chicks to eat the blotting paper with which the bottoms of 
their cages were lined. The importance of an adequate supply of 
roughage seems to have been overlooked by those who have at- 
2 Funk, C., J. Biol. Chem., 1916, xxvii, 3, footnote. 
8 Osborne, T. B., and Mendel, L. B., J. Biol. Chem., 1916, xxvi, 298. 
