N^EW York Agkicultural Experiment Station. 107 



picture (Fig. 2). In the first experiment, the intake of nitrogen 

 was almost constant ; the results of this experiment differ from those 

 of the fourth experiment in that there exists a parallelism between 

 the apparent digestibility of the nitrogen and the phosphorus intake. 

 This is also true of Experiment Three. The second experiment 

 shows no such parallelism, but this should not be given much weight 

 in the argument inasmuch a new factor (nucleo-protein in the rations) 

 is here involved which might be responsible for the discrepancy. In 

 view of all this, one is almost justified in assuming that there may 

 exist between phosphorus and nitrogen metabolism some intimate 

 relationship involved in the synthesis or cleavage of the nucleopro- 

 teins in the organism, but the facts so far established are not sufficient 

 to warrant any conclusion on the fundamental principles here 

 suggested. 



Total phosphorus. — The ingested phosphorus was mostly elimi- 

 nated by way of the intestines. The amount of phosphorus excreted 

 in the urine was relatively very small, as little as one-half of one 

 per ct. of the total outgo of this element on a phosphorus-poor diet. 

 The amount of phosphorus in the urine is readily changed by increas- 

 ing the phosphorus intake (Period IV, Table IVb), as is evident 

 from the study of the data of the phytin period, where the urine 

 phosphorus rose to 15 per ct. of the total outgo. The response to 

 the change in the ration was immediate. Twenty-five grams 

 of phytin were withheld on the forty-sixth day, the next day's 

 urinary phosphorus was 1.31 grams less than on the preceding 

 day; on the fifty-first day, the phytin intake had been reduced to 

 the minimum and the corresponding urine had 90 per ct. less of 

 phosphorus. The same effects are also shown in the other tran- 

 sition periods. In the days between periods I and II there is an 

 immediate drop of 50 per ct. in response to the substitution of 

 washed bran for whole bran. These cases cited above are those 

 of reduction of phosphorus in the rations. When it is a matter of 

 increase the quantitative change is equally striking, but follows a 

 lag of two days. One set of figures will illustrate this point: On 

 the 36th day, there was 0.3 grams P in the urine; 37th day 0.24 

 grams; 38th day, 0.23 grams; 39th day, 3.85 grams; 40th day, 44.1 

 grams P in the urine, the full portion of phytin, 175 grams, having 

 been added on the thirty-seventh day. These quantitative changes 

 of the phosphorus in the urine were not wholly due to the relative total 

 amounts of this element in the rations, but also to the nature of its 

 chemical combination or the internal relations of the phosphorus 

 in the feeds themselves. No other assumption can explain the 

 differences between periods I and IV in which the urine of the former 

 contains less phosphorus than that of the latter, though in its ration 

 there was twice as much phosphorus, and in both periods more than 

 half of the ingested phosphorus was in the form of phytin. In 

 comparing the experiments II and III by Jordan, Hart and Patten, 



