SECRETION OF THE DUCTLESS GLANDS. 881 



tern shows an increased excitability as determined by the response 

 of the nerves to galvanic stimulation. Somewhat similar but more 

 extensive experiments have been reported by Klose and Vogt. 

 When thymectomy is performed on quite young dogs (10 days), 

 very serious consequences result, ending perhaps in a condition of 

 coma and death. These results develop slowly: there is first a 

 stage of increased fat formation and later one of malnutrition or 

 cachexia which manifests itself strikingly in an atrophic and 

 undeveloped condition of the bones, although there is besides a 

 general asthenic or adynamic condition and mental deterioration. 

 Injections of extract of the gland (Svehla) cause a fall of blood- 

 pressure and some quickening of the heart-beat, but these effects 

 are not specific. Unlike the thyroid and parathyroid glands, the 

 thymus contains no iodin (Mendel) . One suggestion made regard- 

 ing its influence is that there is some sort of reciprocal relationship 

 between it and the reproductive glands. Castration (Henderson) 

 causes a persistent growth and retarded atrophy of the thymus, 

 while removal of the thymus (Paton) hastens the development of 

 the testes. Another more specific hypothesis is the one advo- 

 cated by Klose and Vogt in the work referred to above, namely, 

 that the thymus is concerned especially in the processes of syn- 

 thesis of nucleic acid. 



Gudernatsch * finds that young tadpoles fed upon thymus gland 

 are stimulated to excessive growth, while the changes of meta- 

 morphosis to the frog-stage are correspondingly delayed. When 

 thyroid gland is fed, contrary results are obtained. Further 

 growth is inhibited and the changes of metamorphosis are acceler- 

 ated, so that dwarf frogs are produced. This apparently direct 

 proof that the thymus is connected with growth falls in very well 

 with what is stated above in regard to the importance of this 

 organ during the prepubertal period. 



Adrenal Bodies. The adrenal bodies or, as they are frequently 

 called in human anatomy, the suprarenal capsules belong to the 

 group of ductless glands. It was shown first by Brown-Se*quard 

 (1856) that removal of these bodies is followed rapidly by death. 

 This result has been confirmed by many experimenters, and so far 

 as the observations go the effect of complete removal is the same 

 in all animals. The fatal effect is more rapid than in the case of 

 removal of the thyroids, death following the operation usually in 

 two to three days, or, according to some accounts, within a few 

 hours. The symptoms preceding death are great prostration, mus- 

 cular weakness, and marked diminution in vascular tone. These 

 symptoms resemble those occurring in Addison's disease in man, 

 a disease which clinical evidence has shown to be associated with 



* Gudernatsch, "Zentralblatt fur Physiology," 1912, No. 7. 

 56 



