THE ADRENAL BODIES 175 



to a lever in adrenalin solution ; he states that whereas strips 

 from the arteries so tested contract when adrenalin is brought 

 in contact with them, a strip from a coronary artery will become 

 relaxed, and he infers from this that adrenin produces inhibi- 

 tion and therefore vasodilation. Langendorff points out that 

 from a teleological standpoint this is advantageous ; since 

 the adrenin increases the force of the heart-beat, it must be 

 favourable for this action that the calibre of the vessels in the 

 heart- wall becomes increased. Schafer has, however, not 

 succeeded in obtaining the result described by Langendorff, 

 and suggests that possibly there might have been some other 

 substance than adrenin in the solution used. According to 

 some recent experimental investigations carried out by Bar- 

 bour and Prince, adrenin actively dilates the coronary vessels 

 in the dog, cat, rabbit, ox, sheep, and pig, but constricts them 

 in man and the monkey. 



Moore and Purinton recorded a, fall of blood-pressure instead 

 of a rise when very small doses of adrenal extract are adminis- 

 tered. Other authors have from time to time made reference 

 to a depressor constituent of the adrenal. This is not to be 

 wondered at when we remember that, as first noted by the 

 present writer, extracts of tissues generally lower the blood- 

 pressure ; but the presence of a depressor constituent will not 

 explain the result obtained by Moore and Purinton, for there is 

 no apparent reason why the depressor effect should not be 

 swamped by the pressor with small, just as with larger, doses. 

 Pari finds that with freshly prepared extracts there is never a 

 lowering of the blood-pressure, but that with very dilute 

 solutions, which have been kept for some time, this may 

 sometimes be observed. He suggests, therefore, that the 

 depression described by Moore and Purinton was due to chemi- 

 cal changes in the adrenalin in the dilute solution. Pari 

 supports the view of Hunt, that the depressor substance is 

 choline. The matter has recently become of considerable 

 theoretical importance as bearing upon current theories of the 

 function of the chromaphil tissue (see p. 216). Sometimes one 

 obtains, after a preliminary rise, a fall of blood-pressure, even 

 with moderately large doses of adrenin. This occurs espe- 

 cially in my experience with certain commercial preparations 

 when the blood-pressure is high before the adrenin is admin- 

 istered . The fall of blood-pressure with small doses is admitted 



