THE DUCTLESS GLANDS 1325 



principles of ergot. The constitution of these substances is shown in 

 the following formulae : 



CH 3 



)>CHCH 2 CH 2 NH 2 Isoamylamine 



HO/ ") CH 2 CH 2 NH 2 p-hydroxyphenylethylamine 



N > CH 2 CH 2 NH 2 phenylethylamine 



CH(OH)CH 2 NHCH 3 adrenalin 



The formula of adrenalin is placed below in order to show the 

 relation of these substances to the natural hormone. These bodies are 

 produced from the amino-acids of proteins by a process of decarboxyla- 

 tion. Leucine would yield isoamylamine, tyrosine, hydroxyphenyleth- 

 ylamine, and phenylalanine would give phenylethylamine. Such 

 substances may be formed in minute quantities during the normal 

 processes of putrefaction which occur in the alimentary canal. There 

 seems little doubt that we must regard adrenalin as a true internal 

 secretion, and therefore must ascribe to the medulla of the suprarenal 

 capsules, as well as to the other chromamne tissue in the body, the 

 function of maintaining the normal constriction of the arterioles and 

 of facilitating in some way or other the functions of the sympathetic 

 system generally. The absence of this secretion in cases of destruction 

 by disease of the suprarenals would serve to account for the weakness, 

 prostration, and lowered blood pressure of Addison's disease. The 

 two other symptoms of this disease, namely, bronzing and vomiting, 

 still remain to be accounted for. It is possible that the latter may 

 be due to some involvement by the morbid process of the numberless 

 fibres of the solar plexus, which run in close proximity to the supra- 

 renals. We have no knowledge whatsoever of the functions of the 

 cortical power of these organs. It is possible that future work may 

 show some connection between the cortex and the destruction of pig- 

 ment in the body. At present it is only by a process of exclusion that 

 we may guess at a causal relationship between the destruction of the 

 cortex and the bronzing which occurs in Addison's disease. 



THE THYROID GLAND AND THE PARATHYROIDS 

 The thyroid gland consists of two oval bodies lying on either 

 side of the trachea, joined in many animals across the trachea by an 



