430 



METABOLISM, NUTRITION, AND DIET 



accessory bodies. Accessory suprarenal capsules are commonly present in 

 some animals and are sometimes found in man. Further, if one gland is 

 removed, the other hypertrophies. The experiments of all recent observers 

 confirm the original experiments of Brown-Se'quard. The presence of the 

 suprarenal capsules is essential to life. 



Schaffer and Oliver found that injections of suprarenal extract produced 

 marked effects upon the muscular layer of the arteries, the muscular tissue 

 of the heart, and the skeletal muscles. The muscular layer of the arteries 

 is markedly contracted, causing vaso-constriction and a rise of blood pressure. 



FIG. 313. Injection of Suprarenal Extract. 



pressure, after section of cord and vagi. (Reduced to one-half.) 



Effect upon the heart, limb, spleen, and blood 

 (Schaffer.) 



When the heart is freed from nervous control its contractions are increased 

 both in force and frequency, still further raising blood pressure. If the vagi 

 are undisturbed the heart beats more slowly, showing an increase of vagus 

 tone due to stimulation of the vagus center in the medulla. The contraction 

 of the skeletal muscles in response to a single stimulus is increased. 



Very small doses of suprarenal extract are sufficient to produce marked 

 effects. Thus Schaffer states that less than TTGITO g^ 111 ("g^ir 8 ram ) f tne 

 desiccated gland is sufficient to produce an effect upon the heart and arter- 

 ies of an adult man. 



It is a curious fact that only extracts of the medullary portion of the gland 



