330 INTERNAL SECRETION 



phenomenon does not accompany compression of the aorta in 

 cases where the hypophysis has first been destroyed. After the 

 destruction of the hypophysis, it is not possible to produce the 

 vagus pulse by either aortic compression or reflex stimulation of 

 the aorta (by way of the nasal mucosa or trigeminus), the result 

 in every instance being to accelerate the pulse. According to 

 v. Cyon, there is no doubt that stimulation of the vagi, in con- 

 sequence of hypertension within the cranial cavity, is effected by 

 the agency of the hypophysis ; in other words, that the increased 

 pressure acts directly upon that organ and the stimulation of the 

 vagi is reflexly produced by the stimulation of the hypophysis. 



These statements of v. Cyon's do not, however, stand the 

 test of minute investigation and they are entirely unconfirmed 

 by later authors (Biedl and Reiner, Caselli, Pirrone, Lo Monaco, 

 and van Rynberk, Livon, Gaglio). It is true that stimulation of 

 the hypophysis, and electric stimulation more particularly, occa- 

 sionally produces increased pressure and changes in the frequency 

 of the pulse, together with respiratory changes, but similar 

 phenomena may be produced in the same way by stimulation of 

 the greater portion of the cerebral cortex and of the cerebral 

 ganglia. Livon even states that the hypophysis itself is incapable 

 of stimulation, and that the changes are due to the leakage of 

 the faradic stream into the surrounding portions of the brain. 



The destruction of the hypophysis does not bring about 

 changes in either the pressure of the blood or the frequency of 

 the pulse. Moreover, the vagus phenomenon in company with 

 high blood-pressure is observed after, as before, this operation 

 (Biedl and Reiner). 



The theory of a mechanical hypophysal function must be 

 regarded as demolished. The only author who confirmed the 

 phenomena observed by v. Cyon after stimulation of the hypo- 

 physis is F. Masay, and he believes that stimulation of the hypo- 

 physis promotes the flow of secretion from the organ into the 

 blood, and that by its action upon the muscles of the vessels a 

 rise in blood-pressure is produced. 



In the present state of our knowledge, the only assumption 

 possible is that, if the hypophysis does influence the circulation, 

 this result is effected by the agency of a chemical hormone, and 

 is to be regarded as the outcome of the internal secretory function 

 of the organ. 



DISEASES OF THE HYPOPHYSIS IN MAN. 



Of the clinical conditions which are associated with patho- 

 logical changes in the hypophysis and the pathogenesis of which 

 is undoubtedly in some way dependent upon that organ, the 

 most important is the condition first described by P. Marie under 

 the name of acromegaly. This disease usually attacks individuals 



