394 VESSELS OF THE THYROID. [sect. l8o. 



are only a little enlarged, up to o , 05'" in diameter, appearing upon 

 section as transparent, yellowish-white spots or granules which 

 Ecker aptly compares with boiled sago, the structure being other- 

 wise unchanged. In the higher grades of the disease, the vesicles 

 containing the colloid substance become converted into larger 

 cysts, /0'" to 1'" in diameter, in which the epithelium is rarely any 

 longer distinct, although nuclei and pale roundish cells (the latter 

 granular or filled with nuclei) may occur in the cysts along with 

 their abnormal contents. These cysts displace the stroma by their 

 growth, and enlarge also by partial absorption of the walls of the 

 original vesicles. Thus, at length, they coalesce to form still larger 

 sinuous cavities, whose contents are frequently altered in various 

 ways by extravasation, and the metamorphoses consequent thereon. 

 In the lower mammalia, and in birds also, the thyroid occasionally 

 exhibits gland-vesicles slightly distended with colloid matter. 



The blood-vessels of the thyroid are, it is well known, dispro- 

 portionately numerous, but otherwise they present, in their coarser 

 ramifications, nothing worthy of remark. Each lobule receives 

 some small arteries, which, breaking up into subordinate branches, 

 are distributed in the stroma between the vesicles, and, at length, 

 form around each of them a beautiful capillary network, resembling 

 that of the pulmonary vesicles, but with wider meshes. The vessels 

 of the network measure 0*003'" to 0'005"' in diameter, and the 

 interspaces, which are roundish, angular, or elongated, measure 

 from o - oo8'" to o - oi6'". The veins arising from this network only 

 partly follow the course of the arteries, and they exceed the latter 

 in number. Lymphatics also occur in considerable numbers in the 

 thyroid, but their relations in the interior are unknown. Finally, 

 the nerves are scanty, and are only those which belong to the 

 vessels ; they come from the cervical part of the sympathetic. 



Besides the degeneration of the glandular elements, which has been de- 

 scribed, there is another kind of pathological change frequently observed, 

 which results in the production of vascular bronchocele. Here, in addition 

 to a hypera?rnic condition, numerous aneurismal enlargements are found on 

 small vessels of o - o3"' to o'o^" in diameter, which are regarded by Ecker as . 

 arteries or coarse capillaries. By the bursting of such enlargements, there 

 subsequently arise apopletic cysts of different sizes. These cysts and their 

 contained blood may then undergo a variety of metamorphoses, new effusions 

 and exudations being added, and normal tissue becoming also implicated. In 

 the vascular bronchocele, Ecker frequently found also a calcification of the 

 walls of the smaller vessels, numerous calcareous granules dotting their 

 surface, or, in a more advanced stage, obliterating their calibre altogether, so 

 that they appeared like white concretions ; this took place alike in the dilated 

 vessels and in those of normal size. In a certain form of goitre, Rokitansky 



