THE SUPRARENAL SYSTEM 251 



other hand, I have always found that extracts of hypernephroma 

 are negative in their results. 



The above data concerning the variation in the adrenalin 

 contents of the suprarenals, point with some degree of certainty L o 

 the suprarenal tissue as the site of origin of adrenalin. 



The question as to whether adrenalin is formed during life, 

 and is continuously supplied to the blood-stream by way of the 

 veins of the suprarenal capsule, has already been answered in the 

 affirmative in a communication of Vulpian's. Vulpian found 

 that the blood in the suprarenal veins contains the substance 

 which gives a green reaction with ferric chloride. By means of 

 the vaso-contractor action of blood from the suprarenal veins, 

 Cybulski showed that the active substance is formed continuously 

 in the suprarenals and continuously discharged from them into the 

 blood-stream. His results have been confirmed in several direc- 

 tions (Langlois, Biedl, Dreyer), and it has, moreover, been shown 

 that the production of the active substance of the suprarenals is 

 subject to the influence of the nervous system (Biedl). Ehrmann 

 next proved, by means of his more sensitive test with enucleated 

 frogs' eyes, that there is a continuous supply of adrenalin from 

 the suprarenal to the blood-stream. Fie was able to show, more- 

 over, that the amount of the substance supplied varies in different 

 animal species, while in individuals of the same species it is 

 substantially the same. The adrenalin contents in cats is low, 

 in rabbits it is high. Ehrmann concludes that, upon the whole, 

 those animals are most sensitive to adrenalin which have the larger 

 amount of it circulating in their blood. The amount of adrenalin 

 present in the blood in the suprarenal veins of rabbits, is equal 

 to an adrenalin solution of between one in one million and one 

 in ten million, that is to say, .0000005 rm - ' n l c.cm. of blood 

 serum. 



Watermann and Smit found that blood serum from the vena 

 cava produced mydriasis when undiluted only, and they estimated 

 the adrenalin contents of the caval blood at .000001 grm. per 

 cubic centimetre. They found that electric stimulation of the 

 suprarenal, by which all the sympathetic nerve fibres e'ntering the 

 organ are stimulated, produced an increase in the adrenalin con- 

 tents of the blood in the vena cava, for the serum of such blood 

 caused enlargement of the pupil, even in a i : 10 or i : 12 solution. 



The suprarenal secretory process has long proved a subject 

 of interest and investigation to the morphologist. The first point 

 to be considered in this connection is the activity of the chrome- 

 brown adrenal tissue, which was investigated by Stoerk and 

 v. Haberer under exceptionally favourable conditions. They 

 were able to study the secretory process during excessive muscular 

 exertion, and also to study the hypersecretion which accompanies 

 compensatory suprarenal hypertrophy. As the result of their 

 efforts, considerable light has been shed upon the nature of the 

 secretory process of the suprarenal medulla. 



