558 
ME. E. C. BABEK ON THE MINUTE ANATOMY 
fibres and connective-tissue corpuscles. On the surface it also contains fat-cells 
(Kolliker). 
The Gland-vesicles. — The gland-vesicles ( Drusenblaschen , Kolliker) of the thyroid 
gland are described as closed globular bodies, consisting of a very fine homogeneous 
membrane [membrana propria) lined by a single layer of epithelial cells (Kolliker, 
Henke, Verson). Fret, on the contrary, does not believe in the presence of a mem- 
brana propria. He thinks that the connective-tissue wall of denser texture, when 
examined with imperfect methods of preparation, may have deceived earlier observers. 
Authors differ in their description of the epithelial cells. Henle describes them as a 
single layer of flattened cells containing circular nuclei, and resembling a layer of 
epithelium. According to Kolliker they are polygonal, finely granular, transparent 
cells, each with a single nucleus. Frey, again, alludes to them as flattened, cylin- 
drical, nucleated cells. Finally, Verson, in opposition to Henle, lays stress on the fact 
that the cells in the fresh condition are always somewhat higher than broad. Accurate 
measurements of the gland-vesicles and of the epithelial cells are given by the different 
authors, into a consideration of which it is needless to enter here. 
The cavity of the vesicle is described as occupied by a clear viscid fluid (Kolliker 
and Fret) slightly tinged with yellow, and containing much albumin (Kolliker). 
Henle speaks of the contents as clear, and becoming converted by the action of alcohol 
into a firm, somewhat shrunken coagulum. 
These authors all allude to the occurrence of a colloid material in the vesicles, which 
they consider a pathological condition. Kolliker, however, found it in new-born 
children, and Verson “ at an advanced age.” 
The Lymphatics. — Fret, who is the last observer who has worked at these, gives the 
following account of them, as quoted by Henle ( loc . cit.) : — The large lymphatics 
covering the capsule of the thyroid gland take their origin from a rounded network 
which surrounds the secondary lobules. From these there branch off finer arborescent 
canals for the primary lobules, to surround them with perfect rings or with arches more 
or less complete. From these, again, a few finer canals dip down among the individual 
vesicles and end in blind extremities.” In 4 Has Mikroskop und die mikroskopische 
Technik,’ 4th edition, 1871, p= 283, Fret describes the lymphatics as quoted above by 
Henle, until he arrives at the statement that “ a few finer canals not uncommonly dip 
down among the individual vesicles.” He then stops, and does not confirm his state- 
ment of their ending in blind extremities. 
The object with which the present research was undertaken was a minute investiga- 
tion of the lymphatics of the thyroid gland of the dog, with a view to rendering more 
accurate our knowledge of their structure and distribution. In the course of the inves- 
tigation, however, I found it necessary to study more carefully the vesicular and inter- 
vesicular tissue, and was then led to observe certain cells in the latter which have not, 
as far as I am aware, yet been described. I shall therefore treat the subjects of this 
paper under two headings : — I. The Lymphatics ; and II. The Parenchyma. 
