THE PITUITARY 353 



inhibiting its rhythmical contractions, resembling in this respect 

 the extracts of the chromaphil tissues. 



Just as Schafer and Vincent found two separate substances 

 acting on the blood-pressure a pressor and a depressor so 

 Beyer and Peter distinguish two separate substances having 

 respectively the two actions on the intestine just described, 

 the sympathetic inhibitory substance being insoluble in alcohol, 

 the autonomic augmentor substance soluble. 



These effects on the intestine can be repeated at frequent 

 intervals, while the effect on the bladder rapidly becomes less 

 in successive trials. 



It is doubtful how far these effects are truly specific for 

 extracts of pituitary. 



(d) The Stomach. The effects of pituitary extract on the 

 stomach appear to resemble very closely those upon the 

 intestine just described. There is at first some inhibition, 

 which is followed by a powerful and persistent augmentation. 

 The rhythmical movements are very markedly exaggerated. 

 These actions were first noted by Houssay in the frog, and 

 then in other animals and man. 



Clinical observations have been made in the same direction. 



(e) The Pupil. It was discovered by Cramer that pituitary 

 extract dilates the pupil of the enucleated frog ' s eye . Franchini 

 noted also that the serum of animals which have received 

 intravenous injections possesses slight mydriatic properties. 



There is thus a close resemblance between the reactions, 

 due to administration of pituitary (posterior lobe, infundibular) 

 extracts and those so familiarly called forth by means of 

 adrenin. The chief differences consist in the preliminary 

 fall (in some animals) and prolonged rise due to pituitary, 

 and the fact that this drug causes slowing of the pulse after 

 atropine or section of the vagi, in the constriction of the 

 coronary and dilatation of the renal vessels, adrenin .having 

 an opposite effect. 



5. Effects on the Secretion of Certain Glands 



(a) The Mammary Gland. Ott and Scott discovered that 

 injection of pituitary extract into goats causes a marked increase 

 in the flow of milk, Schafer and Mackenzie found that ex- 



23 



