THYREOID IN TURTLES 289 



The gland is subdivided into lobules by larger connective- 

 tissue septa derived from the external fibrous-connective capsule, 

 and the lobules in their turn are subdivided into alveoli by- 

 thinner septa of the same nature. The blood vessels, the lym- 

 phatics, and the nerves run into the intervesicular and inter- 

 lobular septa, where they form a highly complicated network. 

 In the small thyreoid arteries I have not found it possible to 

 demonstrate those thickenings or buds (Schmidt's 'Zellknospen') 

 of which Kolliker ('02) speaks. The intervesicular substance is 

 rather scanty, and is formed of areolar connective tissue, ex- 

 tremely rich in blood vessels, which constitute a capillary net 

 surrounding the alveoli and extending its finest branches into 

 the epithelium. Between each alveolus and the next are scanty 

 delicate elastic fibers which accompany the blood vessels and 

 are derived from the ramifications of the coarser elastic network 

 covering the surface of the gland. The elastic fibers are numerous 

 and well demonstrable onl}^ in the external connective capsule. 

 Toward the interior of the gland they grow thinner and scarcer 

 till they disappear entirely in the walls of the most central of the 

 alveoli. Elastic fibers are more frequent in the thyreoid of 

 young animals. 



Under the microscope the intravesicular colloid does not 

 differ essentiall}^ from that of the human thyreoid. In the 

 interior of the alveoli there are, at times, free epithelial cells, 

 detached from the alveolar walls, as if some cellular desquama- 

 tion had occurred (fig. 3). This condition noted in the thyreoid 

 of individuals suffering from Basedow disease was at first 

 given a pathological significance; later it was seen that it was 

 a normal phenomenon, a form of holocrine desquamation of cer- 

 tain thyreoid cells (Pende, '18). 



The granules of secretion, as in the cells of the human thyreoid, 

 appear larger and less numerous than the granules of fat and the 

 mitochondria. They stain distinctly red (fuchsinophile) with the 

 method of Galeotti. This method, proposed by Galeotti for the 

 study of the granules of secretion, is of the utmost importance for 

 finer cytologic researches and should never be omitted. The 

 fixative for the employment of this method is either Flemming's 



