V THE SUPRARENAL BODIES 219 



18. The Suprarenal Bodies. — The suprarenal bodies 

 are two in number, and are plrtced on the upper edge of each 

 kidney. They are enveloped in an outer coat or capsule 

 of connective tissue from which partitions pass into their 

 interior. In this way each suprarenal is divided up into 

 compartments. In the outer or cortical part the compart- 

 ments are long and narrow, and placed with their long 

 axis at right angles to the surface of the organ. In the 

 centre or medullary portion the connective tissue forms a 

 somewhat coarse network. The elongated spaces in the 

 cortex are filled with large angular cells, placed in rounded 

 groups immediately next to the capsule, but arranged 

 more in columns towards the central parts of the com- 

 partments. The cells which fill the spaces of the medullary 

 network are of irregular shape and usually branched. 

 These cells contain some peculiar substance, of which but 

 little is known beyond the fact that it gives a dark blue or 

 green colour with ferric chloride, and a bi'ight red colour 

 by treatment with oxidising agents. 



The functions of the suprarenal bodies are important, 

 although, as yet, but little understood. When they are 

 both removed from an animal, death speedily ensues, ac- 

 companied chiefly by a nutritional upset of the skeletal 

 muscles. When diseased in man, a similar defect is 

 observed in the muscles, together with nervous weakness 

 and a characteristic "bronzing" or coloration of the 

 skin. They too contribute an internal secretion to the 

 blood. 



Extracts of the medulla when injected into the circula- 

 tion have an extremely marked action in causing a rise of 

 blood-pressure. This is brought about by an extensive 

 constriction of tlie minute blood-vessels (arterioles) of the 

 body, and is due to the presence in the extract of the 

 crystalline substance known as "adrenalin." For 

 instance, if the ear of the rabbit be carefully observed 

 when a dose of adrenalin is being injected into a vein 

 with a syringe the vessels of the ear wiU almost disappear 



