76 Report or tHE DepartTMENT or ANIMAL HUSBANDRY OF THE 
upon this subject has led to a number of feeding experiments at 
this station. 
Aside from the usual increase in cost of food no results have 
discredited the moderate use of animal food from healthful sources. 
In general, rations entirely of vegetable origin have proved much 
Jess efficient than corresponding rations which contained animal 
foods. But it appears that the inferiority is due in some instances 
more to the lack of sufficient mineral matter than to the less 
efficient forms of the other food constituents. 
The data from some of the preliminary feeding trials were pub- 
lished in Bulletin 149. The rations then fed contained equal 
amounts of protein; but in part of the ration from two-fifths to 
one-half of the protein‘ was from animal food, while in contrasted 
rations it was derived mostly from vegetable sources, although 
some came from milk curd. Subsequent experiments have cor- 
roborated the results then obtained and added to their significance 
by furnishing supplementary and more extended information. In 
one series rations in which about 19 per ct. of the dry matter 
and 37 per ct. of the protein came from animal food proved 
superior to rations containing an equal amount of protein derived 
entirely from vegetable food. The rations were similar in nutri- 
tive ratio but the one in which animal food was used contained 
more than twice as much mineral matter and somewhat more fat. 
In another series the deficiency of mineral matter in the one ration 
was made good by the addition of bone ash, so that the propor- 
tions of protein, ash and fat were alike in the contrasted rations. 
With this addition a ration of vegetable food was as efficient during 
certain periods for chicks and hens as a ration containing animal 
food. For ducklings the vegetable-food ration was thus improved 
but still did not approach in efficiency the animal food ration. 
FIRST SERIES OF EXPERIMENTS. 
In this series of experiments ten lots of chicks were fed for ten 
or twelve weeks and four combined lots afterward for either four 
