TURNER, ON TRANSPARENT INJECTIONS. 149 



which it either gives off a branch, or terminates in an ulti- 

 mate lobule. In some instances the ducts possess dilatations 

 on their Avails, which may either be confined to one side, or 

 may exist at corresponding points on both sides. The same 

 mode of termination of the fine ducts in the ultimate lobules 

 does not appear to exist in all cases, but admits of slight dif- 

 ferences. In some instances the duct passes to the base of 

 the lobule, and then from it, as from a centre, the saccular 

 dilatations of the ultimate follicles spring. In others the 

 duct runs for a short distance along the base of the lobule, 

 giving origin in its course to the follicles, which are connected 

 to its sides and extremity. In either case the fine membrane 

 forming the wall of the duct is continuous with the mem- 

 brane constituting the wall of the follicles, so that the cavities 

 of the follicles are continuous with that of the duct. The 

 number of follicles present in an ultimate lobule varies con- 

 siderably in different specimens. There are also great dif- 

 ferences in their shape and size. Some are spheroidal, others 

 laterally elongated, so as to present a more or less oval form ; 

 others again are more pyriform. When distended by injec- 

 tion, they all present convex, smooth, and well-defined out- 

 lines. On account of the general shape of the follicles, and 

 the mode in which they are grouped together in the lobule, 

 they resemble in appearance a bunch of grapes, with which 

 they have frequently been compared. 



The epithelial contents of the follicles are of course com- 

 pletely concealed in the injected portions of the gland; but in 

 those lobules into which the injection has not passed, the 

 shape and general arrangement of the secreting epithelium 

 may be conveniently studied. It frequently happens that, in 

 examining sections of the gland, isolated follicles may be seen, 

 lying perhaps closely together, as if they had originally 

 formed parts of the same lobule, but still separated by slight 

 intervals from each other, having probably become detached 

 from their original connections in the act of making the 

 section. (PI. X, fig. 3.) In these isolated follicles the secreting 

 cells may be generally very distinctly seen. They form a 

 closely packed layer, lining the inner surface of the membrane 

 forming the wall of the follicle. Their shape is spheroidal, 

 so that they form a true glandular epithelium. 



Professor Kolliker, in his ' Microscopic Anatomy/ describes 

 the pancreas as belonging to the compound racemose group of 

 glands, of which the salivary glands and the mucous glands of 

 the mouth may be taken as the type. In his description of 

 the last-named glands, he states that the grape-like appearance 

 of the ultimate follicles is owing to the fine ducts being 

 coiled upon themselves, presenting at intervals numerous 



