316 INTERNAL SECRETION 



of its functional significance. The animals most frequently em- 

 ployed were the cat and the dog, though a certain amount of 

 material has been provided by other animals (frog, tortoise, hen, 

 rabbit). 



Experimental extirpation from the oral cavity of the hypo- 

 physis of frogs, as carried out by Caselli (1900), did not yield 

 results of any value. Gaglio (1902) operated upon frogs and tor- 

 toises by the same method, however, and found that, though some 

 of his animals died very shortly after, apparently as the result 

 of infective conditions, others lived one and a half to three months 

 without pathological symptoms. Boteano, a pupil of Paulesco's, 

 describes (1906) extirpation of the hypophysis of frogs by the 

 supra- and latero-cranial methods ; he found that, two to three 

 days after total extirpation, his animals invariably died, with sym- 

 ptoms of neuro-muscular asthenia ; while control animals operated 

 upon by the same method, the hypophysis being only partially 

 removed or left intact, remained perfectly normal, with the 

 exception of slight symptoms of central nervous stimulation. 



G. Fischera (1905) operated upon hens. He obtained access 

 to the organ from the base of the skull, by means of an incision 

 at the edge of the lower jaw ; with the aid of the thermocautery, 

 he divided the basal sphenoid bone in the middle line, thus laying 

 bare the hypophysis. Of forty hens, eleven died shortly after 

 operation, twenty-nine survived and were destroyed after four 

 months. The autopsy showed that, in eight cases, the hypophysis 

 was undamaged; in seventeen, it was partially injured; and in 

 four, completely destroyed. Operation was followed in the first 

 few days by symptoms of fatigue and depression, which soon 

 passed off. Two of the hens in which the hypophysis had been 

 entirely destroyed showed signs of arrested development. The 

 results of Fischera's experiments led him to conclude that, in 

 young hens, the hypophysis is not essential to life, and that the 

 symptoms which follow its removal are in no way characteristic. 

 Even the arrestation of development cannot be regarded as a 

 constant symptom. 



The extirpation experiments which Gley carried out with 

 rabbits are, on account of their faulty technique, of very little 

 value. Experiments with cats and dogs are the only ones which 

 have supplied reliable information concerning the function of the 

 hypophysis ; this is attributable, not only to the frequency with 

 which these animals have been employed, but to the better 

 operative technique by means of which such experiments have 

 been accomplished. Cats and dogs have been employed as sub- 

 jects for hypophysectomy by a large number of authors 

 (Marinesco, Vassale and Sacchi, v. Cyon, Caselli, Gatta, Kreidl, 

 Biedl, Friedmann and Maass, Delia Vedova, Lo Monaco and 

 van Rynberk, Pirrone, Gemelli). The method which was first 

 employed and was later in most frequent use, was that of opening 



