Fred C. Koch in 



3. The other products of the hydrolysis studied, primary albu- 

 mose, iodothyrin and secondary albumose, show a gradual decrease 

 in activity per unit of iodine in the order given. 



4. The amino-acid fractions precipitated and not precipitated 

 by phosphotungstic acid from the partially hydrolyzed thyreo- 

 globulin still contain very small amounts of iodine and per unit 

 of iodine are either extremely low in activity or entirely inactive. 



5. Tetra-iodohistidine anhydride and iodotryptophane do not 

 possess thyroid activity as determined by the Hunt method. 



I wish to express my thanks to Prof. A. P. Mathews for sug- 

 gestions made in the course of the work. 



