942 GENERAL METABOLISM [pt. hi 



disappearing may be regarded as wholly protein nitrogen, and will 

 therefore correspond to 783 mgm, of protein. Now the maximum 

 intensity of protein combustion within the egg is 80 mgm. per 100 gm. 

 wet weight of embryo per day, and here we have 783 mgm. per 

 30 gm. wet weight of embryo per i| days, or 1740 mgm. per 100 gm. 

 per day. There seems little doubt but that in early post-natal life 

 a utilisation of protein can go on which does not seem to be possible 

 at any earlier stage although the protein is there. This fact fits in 

 remarkably with a number of others and leads to certain specula- 

 tions of much interest, which will be brought forward in Section 9-15. 



Table 115. 



It also raises the question of what relation exists between the com- 

 bustion of protein by the chick in the egg and by the adult hen. It 

 occurred to Fridericia to make a comparison of this sort. Referring 

 to the work of von Knierem and of Schimanski he calculated that 

 the adult hen on an ordinary corn diet, or in a fasting period after 

 such a diet, would excrete an average amount of 0-5 to i-o mgm. of 

 uric acid per gm. body- weight per day. This would be 100 mgm. of 

 uric acid per 100 gm. body- weight per day or 206 mgm. of protein 

 catabolised per 100 gm. body-weight per day, i.e. more than twice 

 as much as the highest point of pre-natal protein catabolism. Fridericia 

 collected the excrement of newly hatched chicks for a day or two 

 after birth, and did not find such large amounts of uric acid as would 

 be expected from Romenski's figures. He found 53*2 mgm. of uric 

 acid per kilo per hour, i.e. 127-5 nigm. uric acid per 100 mgm. per 

 day corresponding to 266 mgm. of protein combusted per 100 gm. 



