
DIGESTIBILITY OF FISH AND POULTRY. Ty 
various cereal breakfast foods, with macaroni, with vegetables, 
legumes and with fruit and nuts may also be cited. Studies 
have also been made of the digestibility of milk, and of various 
meats, especially beef. The data at hand, however, are by no 
means complete, and in view of the importance of definite 
knowledge, much attention is now being given to this phase 
of the subject. 
As regards the digestibility of poultry and fish but little is 
known. Analyses of these foods are extensive, and their 
chemical composition is well understood. The first at all 
elaborate series of investigations of food materials undertaken 
in this country were studies made by Atwater under the 
auspices of the U. S. Fish Commission, in 1878-81, on the 
chemistry of fish. The report of this Station for 1g02 con- 
tained a large number of analyses of poultry. No attempt is 
here made, however, to summarize previous investigations. 
The object is merely to make a contribution to the general 
knowledge of the subject, which, so far as the digestibility of 
these foods is concerned is very meagre. 
DETAILS OF THE EXPERIMENTS. 
The work here reported comprises four series of experiments, 
two with fish and two with poultry. Each series consisted 
of four experiments, so that in all sixteen experiments were 
included. It was the purpose in the investigation, not only to 
ascertain the extent to which fish and poultry are digested, 
but also to compare, as far as possible, the digestibility of 
relatively fat and lean species. In the experiments with fish, 
salmon was used as a type of relatively fat fish, and cod as a 
type of lean fish. In the experiments with poultry, duck and 
chicken were similarly selected. 
In the first series of experiments a simple ration was made 
up consisting of salmon, bread, milk, butter and sugar. This 
was consumed by each of the subjects for three days. The 
remaining series of experiments followed immediately, on essen- 
tially the same diet, save that chicken, cod and duck were 
substituted in turn for the salmon. All the food consumed 
and feces excreted during each experiment were carefully 
weighed and samples analyzed. The urine of the final day of 
each experiment was also collected, weighed, and its heat of 
