248 THE DUCTLESS GLANDS 



and medulla, move in close parallelism with one another in 

 pathological states of the body. On the other hand, stimu- 

 lation of the splanchnic nerves seems to affect chiefly the 

 medulla (see p. 224 et seq.). 



4. The enormous development of the adrenal cortex in the 

 human embryo is possibly connected with the highly developed 

 brain of man. Alexander has suggested, and Kohn supports 

 the suggestion, that the connection may depend upon a 

 lecithin product in the adrenal cortex in accordance with the 

 lecithin requirements of the growing brain. 



It must be confessed that both as to the function of the 

 cortex and as to a possible relationship between it and the 

 medulla, we are still almost entirely in the dark. 



S. Summary of Views as to the Probable Functions of 

 the Adrenal Bodies 



As we have seen above, it is difficult to adduce any satis- 

 factory evidence that the secretion of the chromaphil tissue is 

 of any use whatever in the normal state of the animal. 



We have also seen that the suggestion has been made that 

 the secretion is of great service in certain emergencies. Certain 

 experiments seem to show that during times of emotional 

 stress the adrenal bodies pour into the blood sufficient adrenin 

 to be of some service, possibly in increasing the power of 

 sustained muscular activity. This view has received very 

 general approval, but it would be rash to affirm that it has 

 been firmly established. Stewart and Rogoff conclude that 

 fright has nothing to do with the results. 



The experiments of Hoskins and McClure, taken in con- 

 junction with others above referred to, furnish sufficient 

 evidence to warrant us abandoning the tonus theory of adrenal 

 secretion. But the theory is still put forward by writers on 

 clinical subjects, and is made to account for the low blood- 

 pressure in Addison's disease. The fact is that we have not a 

 single physiological observation (except perhaps the effect of 

 adrenin on the contraction of skeletal muscles) which throws 

 any light on the pathology of Addison's disease. 



The following is a brief summary of what, in the opinion of 

 the present writer, represents the state of our knowledge 

 concerning the adrenal bodies. 



