Charles-Sedgwick Minot 255 



ized by tlie fact that their branches remain distinct. In the second type, 

 on the other hand, the branches unite togetlier and form an anastomosing 

 gland structure, and when this anastomosing condition is found it is 

 associated, not with the development of connective tissue and capillaries, 

 between the epithelial elements of the organ, but, on the contrary, Avith 

 the presence of a sinusoidal circulation. The branching glands with 

 capillary circulation are numerous, and they may arise, as is noted in the 

 table, from either the ectoderm, the entoderm, or the mesothelium. 

 Glands of the second type, anastomosing and furnished with sinusoids, 

 are few in number. The liver is, of course, the most typical and the 

 most important. With the liver we ought perhaps to associate the para- 

 physis, for the recent and still unpublished investigations of Dr. John 

 Warren show that when this gland is highly developed it is of an anastom- 

 osing t}pe, and make it probable that its blood supply is sinusoidal. 



There remains still a third type, which is necessary, because the ducts 

 become obliterated in a certain number of true epithelial glands, which 

 develop primarily with ducts. There results in each case a group of hol- 

 low epithelial follicles, which are characteristic. For this type I propose 

 the name, " ductless epithelial glands." The thyroid gland and the 

 hypophysis are probably the best-known illustrations of this group of 

 glands. Although the morphology of the pineal gland (epiphysis) is 

 obscure, the organ seems at present to belong to our third type. 



Our third Class, C, comprises the false glands, which never develop with 

 ducts. So far as I am aware this statement may be made absolute for 

 all glands of this class. It is true beyond any possible question for most 

 of the glands, which are here to be considered, but it is perhaps as well 

 to note that possibly some of the glands of the first division may be found 

 in some vertebrates to have been primitively provided with ducts. This 

 seems to me possible, but not probable. The first division of the false 

 glands are the epithelioid. They are perhaps exclusively, so far as the 

 essential gland elements are concerned, of entodermal origin, and it has 

 become probable that their circulation is typically sinusoidal. In the 

 present state of our knowledge it would be venturesome to make positive 

 assertions on these two points. In the epithelioid glands we have groups 

 of cells of epithelial origin separated, in the adult at least, from the layer 

 which produced tliem, and brought into intimate relation with blood-ves- 

 sels. A second division comprises the mesenchymal ductless glands, 

 which are similar to the epithelioid glands in their general appearance, 

 but their specific elements are derived from the middle germ layer. x\s 

 an illustration of the duct^-.ss false gland of the first division, I may men- 

 tion the parathyroid; of the second division, the suprarenal cortex. As 



