326 INTERNAL SECRETION 



That pituitary extract exercises a direct contractor influence 

 upon the vessel walls is proved by Salvioli and Carraro's experi- 

 ments with artificial circulation. Dale's experiments, to which 

 reference has been made in a previous chapter, show that pitui- 

 tary extract resembles barium chloride, which is known to stimu- 

 late the involuntary muscles, in that it produces a rise in blood- 

 pressure at that stage of ergotoxin intoxication at which a fall in 

 blood-pressure is produced by adrenalin. Pal, de Bonis, and 

 Susanna tested the action of pituitary extract by O. B. Meyer's 

 method upon portions of arteries obtained from the living ox. 

 According to Pal, pituitary extract produces a contraction of the 

 carotid, mesenteric, and femoral arteries in the same manner as 

 adrenalin, while its action upon the cardiac and renal vessels is 

 the opposite to that of adrenalin. The coronary arteries, which 

 enlarge in response to adrenalin, contract under the influence of 

 pituitary extract. The peripheral portion of the renal artery 

 which is situated in the pelvis dilates in response to pituitary 

 extract, while the proximal portion contracts. 



The direct muscular action of pituitary extract was proved by 

 Cramer and Borchardt, as well as by Pal, by the enlargement of 

 the pupil of enucleated frogs' eyes. 



Special interest is attaching to the discoveries of v. Frankl- 

 Hochwart and Frohlich concerning the effect of pituitrin upon 

 the urinary bladder and the uterine muscles. In cats and dogs, 

 pituitrin stimulates the muscles of the urinary bladder to a mode- 

 rate degree, but it also increases the sensibility to electric stimulus 

 of the autonomous motor nerve to the bladder, namely, the pelvic 

 nerve. The sensibility of the inhibitory sympathetic, the hypo- 

 gastric nerve, is unaltered. Maximal contraction of the uterus 

 muscles of the rabbit is sometimes produced by pituitrin, and at 

 the same time the uterus becomes considerably more sensitive to 

 the influence of the uterine nerves which are supplied by the 

 hypogastrics. Both these results occur independently of the 

 blood-pressure and, like the effects upon the heart and vessels, 

 they are observed after the first injection only. On account of its 

 effect in increasing the sensibility of the muscles of the urinary 

 bladder and the uterus, these authors suggest the employment of 

 pituitrin as a therapeutic agent. 



The effect which the extract of the posterior lobe has upon 

 the muscles of the uterus and intestine is also described by Blair 

 Bell. 



According to v. Frankl-Hochwart and Frohlich, hypophysin 

 does not affect the sensibility of either the nerves of the salivary 

 glands or the chorda tympani, nor does it influence erection, in 

 so far as the latter is produced by peripheral stimulation of the 

 autonomous erection nerve. In opposition to v. Cyon, these 

 authors state that the sensibility of the autonomous vagus 

 supplying the heart is unaffected by the influence of hypophysin. 



