T. B. Osborne and L. B. Mendel 437 
Leghorn chicks in the laboratory. These were fed in groups, 
in a diversity of ways, our aim being to supply suitable pro- 
tein, salts, and ‘‘vitamines”’ of both the water-soluble and fat- 
soluble types. Green food was never used. ‘‘Roughage’’ or 
“‘ballast’’ was furnished in the form of moist paper pulp. Later, 
many of the chicks ate in addition considerable quantities of the 
blotting paper with which the bottoms of the cages were covered. 
The fat-soluble “ vitamine”’ which probably is ordinarily supplied 
by green food was furnished by a liberal amount of butter fat 
incorporated in the various rations fed. 
It was soon made evident in these newer trials that chicks 
directly from the incubator can reach several times their initial 
weight, though fed on the mixtures selected by us, quite as sat- 
isfactorily as when the experiments were begun with chicks 3 to 
4 weeks old. The rations used contained all of the nutrients 
which our experience with rats had led us to assume might be 
essential for growing chicks and in fairly similar proportions. 
Such changes as were made chiefly involved the physical state 
of the food and were in accordance with the results of our obser- 
vation of the habits of these birds. 
We are not yet prepared to furnish an interpretation of the 
unlike growth made by the chicks in the various experiments just 
referred to. The character of the food mixture used was varied 
so frequently that we cannot yet discuss this feature in detail. 
It seems more than fortuitous that the feeding of liberal propor- 
tions of gliadin or wheat gluten has had a favorable influence, 
especially in view of the high esteem in which wheat is held by 
poultrymen. 
In all our different series a considerable number of the chicks 
developed the familiar ‘‘weakness of the legs’ that is variously 
attributed to lack of exercise and other factors incident to indoor 
conditions. By changes in the diet or by outdoor conditions we 
have as a rule been unable to cure completely birds thus affected, 
although some throve fairly well while remaining permanently 
anatomically defective. Nevertheless a few of the experimental 
chicks continued to grow under the supposedly adverse conditions 
of caging and diet, ultimately gaining a weight of more than 1,250 
gm. The appearance of two such birds is shown in the photo- 
graphs taken at the age of 164 days and 1,278 (2) and 1,267 (<7) 
