THE ADRENAL GLANDS 73 



In the first place, the medulla contains numerous nerve cells, 

 belonging to the vegetative, also called the sympathetic nervous 

 system. But these nerve cells are merely minor notes of the 

 symphony. The motif is settled by a majority of large, granular 

 cells, which stain a- distinctive yellowish-brown when the gland 

 is fixed in a solution of bichromate of potash. All chromium 

 salts, in fact, stain the therefore labelled chromaffin cells. The 

 characteristic staining power appears to be dependent upon, or 

 correlated with, the presence of the internal secretion of the 

 medulla of the adrenal, adrenalin. For the content of adrenalin, 

 as calculated chemically, and the depth of stain as seen under 

 the microscope, rise and fall together. Chromaffin reaction and 

 adrenalin content go together. The poisonous skin glands of the 

 toad have been found to give a marked chromaffin reaction, and 

 to contain a large amount of adrenalin. Other masses of cells 

 in the human body, especially along the course of the sympathetic 

 nervous system, have been shown to give the reaction and to 

 contain adrenalin. 



The erratic Brown-Sequard pounded and hammered away for 

 more than thirty years on the importance to life of the adrenal 

 glands, since death occurred so quickly after their removal. But 

 it was not until Schaefer, the Scotch physiologist, (who has done 

 more than any other living man to stimulate study of the internal 

 secretions) found that an extract of them, when injected into a 

 vein, produced a remarkable though temporary rise of the blood 

 pressure, that a real enthusiasm for its investigation was gener- 

 ated. As the upshot, a number of other significant properties 

 besides the first of blood-pressure raising, have been put down 

 to its credit. Chemical tests demonstrated that it originated in 

 the medulla. The exact amount of it present in the medulla, in 

 the blood issuing from the adrenals and in the circulation in 

 general have been determined. The concentration in the blood 

 is about one part in twenty million, while there is about a 

 hundred thousand times as much stored in the gland as reserve. 

 In infections and intoxications, after muscular exertion, and 

 with profound emotions, there is a decrease of it in the gland and 

 an increase in the blood. Pain and excitement, especially fear?*^ 

 and rage, will bring about its discharge from the gland. With - 

 its entry into the blood, there is a tremendous heightening of the 

 tone, a tensing, of the nervous system. The nerve cells become *"~ 

 more sensitive to stimuli, more sugar is poured into the blood 

 from the liver, more red blood corpuscles are squeezed into the 



