FEEDING EXPERIMENTS WITH ABIURET PRODUCTS 47 



Bergell and Blumenthal (61) have also demonstrated that, under 

 pathological conditions, an amino acid, tyrosine, which was not excreted 

 as such after subcutaneous injection into the normal animal, appeared 

 unchanged in the urine if the injections were made after removal of 

 the pancreas. 



Mode of Catabolism of the Amino Acids. 



In the present monograph it is not intended to discuss the course 

 of the catabolism of the amino acids from the purely chemical stand- 

 point, as this will be dealt with in the monograph by Dr. Dakin. It 

 may be said that after the removal of the amino group by the deaminiz- 

 ing ferments (see p. 52) the fate of the nitrogen-free residue resolves 

 itself into the fate of an ordinary fatty acid. Within recent years there 

 has been a most active discussion concerning the chemical processes 

 which are involved in deaminization. Among the most active workers 

 in this field are O. Neubauer and his pupils. Neubauer (300) has pub- 

 lished an excellent paper dealing with the problem and he has drawn 

 up the following scheme of the different forms of catabolism which the 

 amino acids undergo : 



