INFLUENCE OF THE NERVOUS SYSTEM 181 



the action of hormones in the blood. As the suprarenal 

 cortex acts on ammonium carbonate and changes it to pre- 

 urea, it is probable that this salt stimulates the functions 

 of the gland, at least under certain conditions. It was 

 therefore of interest to resume the study of the effects pro- 

 duced by intravenous injections of the ammonium salt. 



"As with amino-acids, both depression and excitation 

 are observed. In the first case the animal was feeble and its 

 respiration remained light and superficial; in the second, the 

 animal was strong, and its respiration became deep. A 

 process of oxidation must therefore take place to activate 

 the suprarenal cortex. 



"These two reaction-types are accompanied by abso- 

 lutely characteristic urinary modifications. When the 

 depression phenomena predominate, the urine contains 

 ammonia; when the tetanus manifestations predominate, 

 the ammonia decreases. Thus by analyzing the urine, all the 

 unseen phases of the experiment are followed. 



"These facts all demonstrate the role of the suprarenal 

 in the development of the nervous excitations attributed to 

 the thyroid, and, it must be added, also demonstrate, the 

 role of the nervous excitation on the functioning of the 

 suprarenals. 



"The main thing to remember is that this experiment brings 

 out with accuracy the nature of the functional and chemical 

 reactions caused by emotion. It was fright that caused the 

 formation in the cortical layer of the cat's suprarenals of 

 the substance X, the preurea which is not normally formed 

 there, but which also appears after the injections of large 

 doses of amino-acids into the veins of parathyroidectomized 

 animals. Here the injection of amino-acids causes a big 

 nervous excitation which determines in the cortex the same 

 reaction as emotion: the formation of preurea." 



THE INFLUENCE OF THE NERVOUS SYSTEM. 



We have seen above how all kinds of morbid states may 

 be cured by injections or ingestions of antigens, and we 

 have pointed out that it is difficult, in these cases, to admit 



