98 ENDOCRINE THERAPEUTICS 



are an exception to the above rule and are 

 dilated rather than constricted. Its property 

 of raising general blood-pressure is due chiefly 

 to the arteriole constriction it causes, and partly 

 to its direct influence in increasing the force 

 of the heart's ventricular action. Compared 

 with the action of adrenalin, it acts directly on 

 the muscle, whereas adrenalin acts on the sym- 

 pathetic nerve always with the exception of 

 the kidney arteries it acts on all unstriped muscle, 

 whereas adrenalin has an inhibitory action on the 

 abdominal group ; its action is more prolonged 

 than that of adrenalin. Another difference that 

 in practice must be remembered is that while 

 adrenalin dilates the coronary arteries, pituitrin 

 contracts them and the pulmonary also. Why 

 the combined injection of adrenalin and pituitrin 

 should give such relief in asthma, as it undoubtedly 

 does, requires some thought probably the pitui- 

 trin acts chiefly in bracing the heart, while 

 adrenalin acts as a vaso- dilator on the coronaries, 

 and especially on the pulmonary arteries, and at 

 the same time increases oxygenation. 



Professor Sajous, whose work commands and 

 deserves the greatest respect, looks upon the 

 posterior pituitary not as a true endocrine gland, 

 but as a most important governing centre of the 



