160 



PHYSIOLOGY 



tract are particular expressions of general changes in the or- 

 ganism in which the thyroid participates. 



The influence of the parathyroid and thyroid tissue on the 

 creatinine-creatine balance in incubated extracts of muscle tis- 

 sues has been followed by Hammett ('21), His results indicate 



TABLE 116 

 The age and sex distribution of the animals the thyroid extracts of which were tested, 

 together roith the averages of the intestine-contracting poiver of the extracts ac- 

 cording to the individual age groups 



that the addition of parathyroid tissue to extracts of muscle 

 tissue, in acid, neutral or alkaline mixtures, directly retards the 

 increase of creatinine formation normally occurring under these 

 conditions. The addition of thyroid tissue to similar extracts is 

 without effect. 



Removal of the thyroid plus the parathyroids, and of the para- 

 thyroids alone. Hammett 1921-1924 has made a series of obser- 



