THE PITUITARY 361 



in the blood-pressure and in the number and intensity of the 

 heart-beats. These variations occurred to some extent as the 

 result of the trephining, but were much exaggerated by a very 

 slight electrical stimulation. Cyon worked with rabbits, and 

 noted a considerable slowing of the heart- beat, with increase of 

 amplitude. 



Different results have been obtained by the majority of 

 subsequent workers ; but Masay obtains results similar to those 

 of Cyon, though his interpretation is different. The effect of 

 direct stimulation of the gland he attributes to an increased 

 discharge of the internal secretion into the blood-stream, 

 where it produces the usual result due to the action of the 

 extract upon the heart. 



Schafer reports that, in dogs, partial injury to the pituitary 

 by means of a thermo -cautery or mechanical agents induces 

 marked diuresis. This result is specially interesting in relation 

 to the polyuria, which occurs in injuries and tumours affecting 

 the base of the brain. This polyuria is more likely to occur 

 when the pars intermedia is involved. 



I. Extirpation Experiments 



The first to perform experimental extirpation of the pituitary 

 was Horsley, in 1886. Subsequent observers obtained con- 

 tradictory results ; but it was established by Paulesco, in 1906, " 

 that the organ is essential for life, and that the onset of the acute 

 symptoms depends on the loss of the anterior rather than on 

 that of the posterior lobe. Paulesco's results have been con- 

 firmed in the main by Gushing and his co-workers. These find 

 that puppies survive total extirpation longer than do adults ; 

 that life can be prolonged (see Section G) by transplantation 

 of the removed gland ; that, in all cases which recovered, a 

 fragment of the anterior lobe was invariably found to have 

 survived ; that animals with a fragment of anterior lobe, 

 temporarily insufficient to support life, could be tided over a 

 period of threatened cachexia hypophyseopriva by subcuta- 

 neous injections, or by feeding with anterior lobe ; and that 

 removal of the posterior lobe leads to no very definite 

 symptoms. 



The acute symptoms observed were tremors, fibrillary 

 twitching, arching of the back, insensitiveness, slow pulse and 



