184 SPECIAL HISTOLOGY. 



which the fission of the primary vesicular rudiment, observed by 

 Remak, would be merely the first phase. In this respect, also, 

 a certain resemblance with the thymus would be established, 

 only that in the latter, both the buds of the primary rudiment, 

 as well as the later ones, are not detached, but all remain in 

 connexion. The follicles of the thyroid gland, therefore, 

 would not be any kind of enlarged cells, and still less meta- 

 morphosed nuclei (Rokitansky), but be equivalent to true gland- 

 follicles. 



The investigation of the vesicles of the thyroid gland has 

 mainly been pursued in animals, especially in Birds, Amphibia, 

 and in children ; and sections obtained by means of the double- 

 bladed knife, or glands that have been hardened, are most 

 suitable for the purpose of studying the vesicles in detail, and 

 in their mutual relations; but the same object may also be 

 attained by minute dissection, and the teasing out of the 

 structure. Injections are very easily made and run very finely 

 in children ; they best exhibit the plexuses around the vesicles, 

 in sections taken from the surface. 



Literature. — Schwager-Bardeleben, 'Obs. micr. de glandu- 

 larum ductu excret. carentium structura/ Berol. 1841, Diss. ; 

 Panagiotides and K. Wagener, 'Einige Beobachtungen iiber 

 die Schilddriise/ in Froriep's <N. Notiz/ Bd. XL, p. 193; and 

 Panagiotides, ' De gland, thyreoidese structura penitiori./ Diss. 

 Berol., 1847; A. Ecker, ' Versuch einer Anatomie der primi- 

 tiven Formen des Kropfes, &c./ in 'Henle and Pfeufler's 

 Zeitschrift/ f. rat. Med. VI, Bd., p. 123, and Article < Blood- 

 vascular glands/ in Wagner's ' Handw. d. Physiol/ III ; Roki- 

 tansky, in ' Zeitsch. d. Wiener Aerzte/ 1847, and ' Zur 

 Anatomie des Kropfes/ in f Denkschriften der kaiserl. Akad. 

 zu Wien/ Bd. I, Wien, 1849. 



OF THE THYMUS. 



§ 182. 



The internal thoracic gland or thymus, also one of the 

 so-termed blood -vascular glands, is a bilobate, elongated, 

 flattened organ, broad inferiorly, invested and united to the 



