C. Crowther and H. E. Woodman 



47 



cows for each respective jjeriod. The weight columns give the gain or 

 loss of weight of the cows over the whole period. 



Table III. 

 Sunuiiurij of nitroyen-halances for Cow C and Can' D up to da// 295. 



Daily ration: 20 llj. seeds hay (average dry matter per day = 7600 gm. ). 

 Cow C Cow D 



Analytical Total N 

 days consumed 



2.55 37,016 gm. 



Condensed suni.tnanj. 

 Total N retained 



Nett change of weight 



Cow C 

 800 gm. 



* Includes small amount of nitrogen tnn 

 trial). 



Initial weights of eow^ 



According to current views on protein metabolism we might expect 

 to find, on introducing a given ration supplying protein in excess of the 

 requirements of the basal metabolism, that nitrogen storage took place 

 at the outset, but that the rate of storage steadily fell until nitrogen- 

 equilibrium was re-established. This process is clearly evident in the 

 records of our two cows. Taking Cow C for example, and overlooking 

 the first 20 days as preliminary, it will be seen that the nitrogen-retention 

 steadily fell and nitrogenous equilibrium was ultimately roughly estab- 

 lished, though not until the lapse of about 90 days. Subsequently, 

 between days 93 and 194 the cow was in almost perfect nitrogen-equi- 

 librium, but this was then disturbed by a rise in nitrogen-consumption 

 due to an abrupt rise in the protein-content of the hay. The effect of 



