NERVOUS AND ENDOCRINE CONTROL I5I 



since pedigree tabulations are known which clearly show that the condi- 

 tion can be transmitted from the paternal side. 



As to just where to draw lines among hormones, vitamins and other 

 chemical substances of the body which likewise produce pronounced 

 physiological effects when present in almost unbelievably small amounts, 

 no one can yet say. The vitamins are of dietary origin. Absence of any 

 one of them from our food results in its own particular type of disorder. 

 The chemical structure of a number of both the vitamins and the hor- 

 mones is now known and that of others is in fair way of solution. It is 

 a significant fact that calciferol, the active principle of Vitamin D which 

 is sometimes called the sunshine vitamin, belongs in the same chemical 

 group (the sterols) with the male and the female sex hormones. An even 

 more surprising fact is that the cancer-producing constituent of coal tar 

 has a type of chemical structure that also suggests the nucleus of the 

 sterols. Nor is this relationship of the sex hormones and the cancer in- 

 citant merely a fanciful one, for when the latter is injected in properly 

 graduated dosage into rats, reactions characteristic of female sex hor- 

 mones are initiated. 



Then, too, there are the recently discovered neurohumors — chemical 

 mediators between nerve endings and the organs to which their impulses 

 are transmitted. Some endocrinologists would recognize these as true 

 hormones. If so, the distinction which we commonly make between 

 endocrine and nervous regulation of the body becomes decidedly ob- 

 scured. The rate and force of the heartbeat, for example, is controlled by 

 two different nerves. Impulses from the vagus nerve render the beat 

 weaker and slower, those from the cardiac-sympathetic nerve, stronger 

 and faster. It has been discovered that the vagus produces its effect by 

 the release of a minute amount of acetylcholine; the sympathetic operates 

 by discharge of a substance very Hke adrenahn, called sy7npathin, of which 

 there are apparently two types, E. and I. The evidence is increasing, in- 

 deed, that transmission of all impulses from nerve fibers to receptive cells, 

 whether glandular, muscular or even other nerve cells, is of this same 

 chemical type. 



And now what of romance, of drama? Has it all vanished into the 

 neutral drab of everyday scientific fact? Why, as someone pointed out, 

 even the dramatic tragedy which thrilled us in our childhood that Jack 

 Spratt could eat no fat, his wife could eat no lean, is doubtless reducible to 

 a mere difference in endocrine complex. Possibly Jack was a cadaverous 

 hyperthyroid and his buxom wife a slightly hypothyroid individual. And 

 probably old King Cole was a merry old soul merely because of well- 

 balanced endocrines. At least it is certain he would not have been merry, 

 had they been much out of balance! The broad fat tenor or the long thin 

 bass, is possibly but the puppet perpetrated by his hormones. Thus always 

 is the scientist taking the joy out of life by destroying our most cherished 



