FEEDS AND FEEDING I469 



day's duration the present series of experiments was carried out to amplify 

 the data obtained. 



The animal emplo)^ed was an Airedale bitch weighing 17.6 kilos. She 

 was fed daily at 11 a. m. after catheterisation, the urine then obtained 

 being added to the urine collected in the receiver of the metabolic cage. 



The anah^tical methods employed were : total nitrogen, Kjeldahl ; 

 urea, Phmnier and Skelton's modification of the urease method, ammonia, 

 Fohn. The delimitation of the faeces was carried out by means of charcoal 

 or carmine. The total faeces was collected for each period and a single 

 analysis of the mixed specimens was made. 



As regards the standard diets employed three different combinations of 

 protein, fat and carbohydrate were used. They all contained the same 

 amount of protein and were of the same caloric value but varied markedly 

 in their content of fat and carbohydrate. They were as follows. 



I. Carbohydrate-rich, fat-poor diet. 



Scott's oatfloiir . . . = 120 g 



Dried skimmed milk = 43 g 



Margarine = 34 g 



Caseinogen = 19 g 



Tapioca = 93 g 



Sodixim chloride . . =^ 2 g 



Nitrogen . . . 7-- g- 



Carbohydrate. . 194 g. 



Kat 34 g. 



Caloric intake . I2<i6 



II. Intermediate diet. 



Scott's oatflour ... = 60 g 



Dried skimmed milk = 62 g 



Margarine = 77 g 



Caseinogen = 19 g 



Tapioca = 47 g 



Sodium chloride. . . =^= 2 g 



Nitrogen ... 7-2 g. 



Carbohydrate. . 117 g. 



Fat 68 g. 



Caloric intake . 1206 



III. Fat-rich carbohydrate-poor diet. 



Scott's oatflour. . . = 30 g. 

 Dried skinnned milk --- 40 g. 



Margarine — - 120 g. Nitrogen. . . . 7.2 g. 



Cjiseinogen = 34 g. Carbohydrate. . 42 g. 



Fat 1 01 g. 



Sodium chloride . . 2 g. Caloric intake . 1296 



The standard diet was continued for a pre-period of five to eight days 

 until the nitrogen outptit was approximately constant, there was then 

 added to the diet a definite amount of protein material, and this was con- 

 tinued for eight days when the diet again reverted to the original standard 

 for a post-period of six or eight daj^s. It was thought that in this way 

 some definite information as regards retention would be obtained. 



A short bibliography is given and tables show the results of the five 

 experiments, which were as follows : 



