396 CHARLES B. STOCKAED 



In these tails the genetic constitution of the tissues is the 

 determining- factor for their pattern of growth in spite of 

 the composition of the endocrine environment. A similar 

 statement is no doubt true in regard to a number of other 

 modified growths which at first sight might seem to be re- 

 sponses to strange endocrine complexes. On the other hand, 

 a number of structural modifications do result primarily from 

 definitely inherited alterations in endocrine composition; 

 overgrowth of skin and various disharmonious arrangements 

 of parts are examples of this. The genetic constitution must 

 determine the endocrine qualities, and the patterns of growth 

 for certain tissues may be influenced by these, yet the pattern 

 of growth for other tissues or parts may take place over 

 and above such influences. These two courses of development 

 in abnormal expression must constantly be differentiated, not 

 only among these dogs but also for man and other mammals. 



