GLANDS AS AN INTERLOCKING DIRECTORATE 99 



It is important to get clearly in mind these subtle inter-reac- 

 tions of the different ductless glands. They may be antagonistic 

 in their end effects because of the opposed functions of the nerves 

 or organs stimulated. There are inhibitions and restraints pro- 

 duced when a gland will send out its secretions to stop another 

 gland secreting. There are compensations resulting when be- 

 cause of insufficiency of a gland, others will endeavour, by manu- 

 facturing more of their own secretion, to compensate for the loss. 

 There are mutual co-operations, partnerships, when a gland will 

 oversecrete to assist another, or in response to another which is 

 also oversecreting. There are losses of balance, so that when 

 one gland ceases secreting, another will simultaneously or soon 

 after. Normal secretion, oversecretion or undersecretion are 

 thus adjusted, but leave a train of after effects. 



So with loss or insufficiency of the thyroid, there may be 

 pituitary overgrowth, because the pituitary may act as vicar 

 for the thyroid. The thyroid and thymus are antagonistic, for 

 the thyroid hastens differentiation, puberty and the coming of 

 sexual maturity, while the thymus delays and retards them and 

 prolongs the period of childhood. The thyroid and the pancreas 

 are antagonists, for when the thyroid has been excised, the 

 pancreas appear no longer necessary to act as a break upon the 

 mechanism of sugar liberation into the blood from the liver. 

 The thyroid stimulates the interstitial glands, for menstruation 

 and pregnancy are impossible with no thyroid or an insufficient 

 thyroid. Removal of the pituitary makes the thymus shrink 

 because the restraining influence of the latter is no longer needed. 

 But there is an enlargement of the thyroid to compensate. In 

 castrates there is an increase in the size and number of the cells 

 of the anterior pituitary, again a compensation or substitution 

 effect. The pituitary and the adrenal cortex are mutually assist- 

 ant, alike in their influence upon the tone of the brain and sex 

 cells. 



The Kinetic System 



So there are combinations of glands to assist or restrain others, 

 or to control a body function, or to determine the domination 

 or abeyance of an instinct. One such has been named the kinetic 

 system because it comes into play in situations which demand 

 prompt adaptation without hesitancy, and a consequent imme- 

 diate transformation of static or stored energy into kinetic or 



