STRUCTURE AND DEVELOPMENTAL RATE 253 



A slowing of the developmental rate at particular times may 

 largely suppress the growth of certain organs, rendering them 

 abnormally small in size and insufficient in their function. The 

 normal proportion of things becomes distorted. Again it may 

 rarely happen that one organ takes on an excessive growth and 

 attains a size entirely out of normal proportion. There is thus a 

 frequent lack of proper balance and adjustment among the several 

 organs of the developing body. 



The properly regulated balance among the organs is to a great 

 extent due to the inhibiting and controlling effects of one growing 

 region or part over other parts. This is readily demonstrated 

 by the modifications which result in size and proportion of certain 

 parts of the body following the experimental removal of other 

 parts. All parts may be thought of as having more or less to do 

 with the ultimate growth results of the whole. 



On becoming adult, a state of apparent balance is maintained. 

 Growth is considerably reduced and largely confined to the repair 

 of natural loss and the maintenance of this state of adult balance. 

 Under such conditions there still remains considerable regenera- 

 tive powers following injuries of various kinds. Yet these regen- 

 erative processes are not so perfectly accomplished or so well con- 

 trolled in the adult animal body as they were in the larval or 

 immature condition. This fact may in some way be associated 

 with the absence in the adult of general growth and the well- 

 expressed regulatory processes which are necessary in the devel- 

 oping individual. 



The regenerative growth following injuries to the adult animal 

 may become morbid in degree and without regulation, thus giving 

 rise to malignant conditions. Such a growth might rarely occur 

 in the immature body, but in this case one would expect to find 

 the growth proportions among the tissues in general to be abnor- 

 mal and distorted. Thus, juvenile cancer conditions are rare and 

 are probably associated with other deformities. 



Cancer in the adult would be expected to occur more fre- 

 quently in certain families, since the growth balance and propor- 

 tions are hereditary characters, and on the state of these, the can- 

 cerous growth largely depends. Families or persons derived from 



