978 THE INTERNAL SECRETIONS 



part, because the subsequent experiments of Caselli (1900), Gaglio 

 (1902), Fischera (1905), Aschner (1912), Biedl (1913), and Gushing/ 

 have given practically identical results. Only a few of the hypophy- 

 sized animals survived for a longer period than two or three months, 

 and in these it was impossible to determine whether any of the essential 

 tissue had been left behind. It was also demonstrated in these animals 

 that the two lobes of this organ possess different functions, the extirpa- 

 tion of the anterior one proving fatal immediately, while that of the 

 posterior one did not produce decisive symptoms for some time there- 

 after. In the latter case, the animals usually died from some incurrent 

 condition. Likewise, no immediate symptoms developed after the 

 partial removal of the anterior lobe, the animals meanwhile acquiring 

 extensive layers of fat in the omentum and retroperitoneal spaces, 

 and gradually developing a condition very similar to infantilism. 



Pituitrin. — Subsequent to the observation of Oliver and Shafer,^ 

 that the extract of the hypophysis gives rise to a marked increase in 

 blood pressure, a substance was isolated from the posterior lobe to 

 which the name of pituitrin or hypophysin has been given. ^ When 

 injected into the venous blood-stream, this agent raises the arterial 

 pressure very materially as well as for a considerable period of time. 

 There is no doubt that this hypertension originates chiefly in a con- 

 striction of the peripheral blood-vessels, 5,lthough this substance also 

 seems to strengthen and to slow the heart beats. When compared 

 with the action of adrenalin, it must be conceded that it produces a 

 much more lasting although not quite so powerful effect, and that its 

 action is exerted upon the muscle tissue directly and not upon the 

 nervous terminals.^ 



The Function of the Posterior Lobe of the Hjrpophysis. — When 

 studying the action of extracts of the entire posterior lobe, it must 

 be remembered that the active principle here involved is a product of 

 its glandular pars intermedia and not of its n^uroglia-like posterior 

 portion. When injected intravenously, such extracts cause the smooth 

 muscle tissue throughout the body to contract, thereby constricting 

 the arteries and arterioles and raising the arterial pressure. The 

 same effect is produced upon the urinary bladder and uterus, both these 

 organs being contracted very powerfully but more so by the first 

 injection than by the subsequent injections.^ Upon this action is 

 based the therapeutic value of pituitrin as an agent promoting the 

 emptying of the pregnant uterus, but its application in obstectrical 

 practice should be restricted to particular cases. It is a safe agent in 

 the hands of only the mOst experienced practitioners. 



1 The Pituitary Body and Its Disorders, 1912, also see : Houssay, La accion fis. 

 de los extr. hipofisiarios, Flajban, Buenos Aires, 1918. 



2 Jour, of Physiol., xviii, 1895, 23. 



3 Engeland and Kutscher, Zeitschr. fiir Biol., Ivii, 1911, 527. 



4 Cramer, Quart. Jour. Exp. Physiol., i, 1908, 189. 



^ Frankl-Hochwarth and Frohlich, Wiener klin. Wochenschr., 1909. 



