THE THYMUS GLAND 115 



In young hens, operated upon when two to five days old, there was 

 weakness of the legs, tremor of the entire body, and, finally, a 

 somnolent condition ending in death. The removal of one lobe 

 only of the thymus was followed by a transitory weakness, from 

 which the birds quickly recovered. In birds of more than a week 

 old, the removal of the whole of the gland, like that of one lobe, 

 was not followed by pathological signs. 



Abelous and Billard (1896) describe the remarkable results 

 which follow extirpation of the thymus in the frog. According to 

 these authors, frogs live from three to, at the outside, fourteen days 

 after total extirpation ; death is accompanied by intense muscular 

 weakness, trophic disturbances of the skin (pallor, ulceration), 

 changes in the nature of the blood (decrease in the number of 

 red blood-corpuscles, leucocytosis) and general oedema. Removal 

 of one lobe of the thymus is not dangerous to life, but extirpation 

 of the portion left in situ is followed by the symptoms described. 

 If the remaining portion is not removed until fifteen to twenty 

 days after extirpation of the first, it will show a certain amount 

 of hypertrophy. 



Camia is the only author who is able to confirm these results. 

 The careful investigations of S. Vincent, ver Ecke and, more 

 particularly, of Hammar, led them to different conclusions. 

 Hammar found that, during an observation period of twelve to 

 fifty-nine days after total thymectomy, his frogs showed no 

 symptoms of pathological disturbance. It seems probable from 

 Pari's experiments, that the symptom-complex seen by Abelous 

 and Billard was due to the accidental infection of their subjects. 

 Moreover, Hammar and ver Ecke found that removal of one side 

 of the thymus was not followed by compensatory hypertrophy 

 of the other side ; on the contrary, owing to reduced nutrition, 

 there was a more or less clearly defined accidental involution. 

 Hammar concludes that the thymus is not more necessary to life 

 in the frog than it is in mammals. 



Experiments with mammals are described by Carbone, Ghika* 

 Ventra and Angiolella. Carbone found that thymectomized 

 rabbits and a thymectomized dog did not differ in their develop- 

 ment from control animals of the same litter, and that they 

 showed only a passing reduction in the number of their red blood- 

 corpuscles. Ghika removed the thymus from eight cats and 

 thirteen rabbits ; he found that in the first few days there was 

 emaciation and arrest of development which lasted for weeks, 

 though in some of his animals the losses were afterwards made 

 good. In his opinion, the thymus is concerned in the formation 

 of blood and the promotion of growth. Ventra and Angiolella 

 saw cachexia, similar to that which follows extirpation of the 

 thyroid, in young animals after thymus extirpation. 



In 1903, K. Basch first published the results which he 

 obtained by experimental extirpation of the thymus; he added 



