i INTERNAL PROTECTIVE SECRETIONS 61 



forms salts with different acids. It is not an alkaloid. It 

 oxidises readily, and is therefore strongly reducing, and can be 

 used as a developer in photography. Adrenaline has a marked 

 vaso-constrictor action. A cubic centimetre of O'l per cent solution 

 injected into the vein produces an increase in arterial pressure of 

 30 mm. Hg in a dog that weighs 8 kilos. When applied to the 

 conjunctiva it incites marked local ischaemia, of short duration, and 

 on this account is much used in ophthalmology. It has also been 

 resorted to successfully in severe catarrhal hyperaemia of the 

 external niucosae. According to Vassale the active suprarenal 

 principle also has a therapeutic action when introduced into the 

 stomach in gastric and intestinal atony. 



In pursuance with the idea expressed above that the suprarenal 

 capsules consist of two distinct organs, and that maximal import- 

 ance must be ascribed to the medullary substance (chromaffine 

 tissue, capsular paragangliori), various attempts have been made 

 to determine which of the two substances, cortical and medullary, 

 is the seat of the active principle. 



Salvioli and Pezzolini noted a marked difference in the 

 efficiency of the extract of medullary substance, which they found 

 to be greatly in excess of that of the cortical substance. Oliver 

 and Schafer (1895) had previously concluded from their experi- 

 ments that the active vaso-constrictor principle of the suprarenal 

 capsules is contained solely within the medullary substance. The 

 very weak effects which they sometimes observed after injection of 

 cortical extracts were due to post mortem processes of diffusion of 

 the medullary juice and other accidental contamination. Vassale's 

 recent work has fully confirmed these conclusions. 



On the other hand, Langlois (1898), Swale Vincent (1896-97), 

 Biedl and Wiesel (1902), have shown that extracts of the extra - 

 capsular chromaffine tissue of the lower vertebrates (Amphibia, 

 Selachia) have the same action, while according to Biedl and 

 Wiesel the extracts may be made indifferently from the medullary 

 substance of the capsule, or from other accumulations of chrom- 

 affine tissue in these animals. Vassale therefore thinks it more 

 correct to give the name of paragangline to the active suprarenal 

 principle, which he prepared exclusively from the medullary sub- 

 stance of the suprarenal capsules. 



It must, however, be noted that Vassale's paragangline is not 

 a chemically pure and crystallisable substance like Takamine's 

 adrenaline, but is an extract which contains the vaso-constrictor 

 principle in strong concentration, along with diastatic ferments, 

 and an abundance of lecithin, which has been demonstrated by 

 numerous observers in the medullary substance of the capsules 

 (Croftori, Alexander). Vassale himself admits " that adrenaline 

 is to paragangline as morphine is to opium." 



Another series of recent researches was directed to solving the 



