Studies in Thyroid Activity. 



pain and great weakness felt in the back and certain sensations of 

 cold felt on the head. 



Solution B was found: (i) to change the dry, scaly, rough skin 

 to a soft and entirely normal condition, which allowed perspiration 

 to take place; (2) to remove the soreness of bones and joints; (3) 

 to prevent cramps and twitching of the muscles; (4) to have a 

 marked effect on the mental activity, especially noticeable in 

 cretins; (5) to relieve the hard, firm condition of the flesh, allowing 

 it to become soft and pliable; (6) to prevent burning sensations 

 which flash over the skin from one part of the body to another. 



Solutions A and B act independently of each other. Further- 

 more, each of these solutions has been subdivided and the various 

 constituents separated have continued to act independently. It 

 would thus appear that each function of the thyroid gland is due 

 to the specific physiological activity of the separate and distinct 

 chemical constituents of the gland. Baumann claimed that 

 iodothyrin is the active principle of the thyroid gland. It is 

 evident that there is no one active principle of the thyroid gland, 

 but that there are many, each with its own specific action. The 

 separation of the various constituents makes it possible to treat 

 cases of thyroid deficiency with those portions of the gland whose 

 deficiency is indicated by the symptoms. Furthermore, it will 

 be possible to standardize the active principles of the thyroid 

 gland by a method based on chemical analysis. 



I wish to thank Dr. F. C. Wood and the attending physicians of 

 St. Luke's Hospital for the opportunity of carrying on this in- 

 vestigation, and Mr. A. W. Thomas for assistance in the chemical 

 laboratory. 



Further work is being carried on, both with the chemical separa- 

 tion and identification of the various constituents and with the 

 physiological activity of the same. 



