FEEDING THYMUS TO FROG LARVAE. 117 



cats and thirteen rabbits; he found that in the first few days 

 there was emaciation and arrest of development which lasted 

 for weeks, although, in some of the animals, the losses were 

 afterwards made good. 



Cozzolino removed the thymus from young rabbits weighing 

 300-400 gm., and in the first two months after the operation 

 was unable to detect any change in their condition. 



In a later communication, however, he described crookedness 

 of the legs, arrest of growth, and progressive cachexia in one 

 animal upon which he had operated three months previously. 



S. Vicent extirpated the thymus of guinea pigs and did not 

 observe any changes in their condition. 



Paton and Goodall found that extirpation of the thymus pro- 

 duced no effect upon the general growth and development of 

 new born guinea pigs. 



R. Fischel extirpated the thymus of goats, rabbits and dogs, 

 and obtained negative results. He concluded from his experi- 

 ment, that thymectomy has no effect upon the development of 

 the subject. 



The work of this author has been severely criticized by Basch, 

 who claims that the experimental conditions were inappropriate. 



Basch extirpated the thymus of suckling dogs and obtained, 

 striking changes in the growth of his thymectomized animals. 

 The most important growth changes were those affecting the 

 skeleton. 



U. Soli found that thymectomy was followed in young rabbits 

 by changes in the development of the skeleton, these changes 

 affecting the hollow, long bones and ribs. This author failed 

 to confirm the results obtained by Basch, with guinea pigs, in 

 which thymectomy is a comparatively simple operation. This 

 would seem to indicate that the symptom complex, observed by 

 Basch following thymectomy in his animals, was probably due 

 to post-operative changes and not connected with the thymus, 

 because in those animals used by Basch, thymectomy is a very 

 severe operation. 



Hainan and Marshall extirpated the thymus of young guinea 

 pigs, and found that removal had no influence upon the growth 

 of these animals. 



