358 THE PANCREAS. THE SPLEEN. [SECT. 165. 



gland- vesicles, join together into larger canals, and ultimately 

 form, by their union, the ductus Wirsungianus. They are whitish 

 and rather thin-walled, they are composed solely of connective 

 tissue with elastic fibrils, and they all possess an epithelium of 

 small cylindrical cells, which scarcely exceed o - oo6'" to o - oo8'" in 

 length, and 0*002'" in breadth. In the walls of the ductus Wir- 

 sungianus, and its larger branches, are placed numerous small 

 racemose glandules, o , o6'" to o'o8'" in diameter, with vesicles of 

 o*o 16'" to 0'02'", whose epithelial cells contain but little fat : these 

 are nothing else than mucous glands, analogous to the glands of 

 the bile-ducts. According to Verneuil, the canal from the head of 

 the pancreas not only opens into the main duct, but has also a 

 separate narrow aperture into the intestine; in its course this 

 D. pancr. azygos ( Verneuil) passes indifferently over or under the 

 larger duct. See Beau et Bonamy, iv., pi. 34. 



The pancreas possesses the ordinary connective tissue of glands, 

 with a variable number of fat-cells, and in this the vessels and 

 nerves of the gland branch out. The former present exactly the 

 same conditions as in the parotid, only that the lymphatics appear 

 to be more numerous ; and with regard to the latter, it appears 

 that they accompany the vessels only : they spring from the sym- 

 pathetic, and contain fine fibres of medium thickness. The secre- 

 tion of the pancreas is, normally, a clear fluid, any solid particles 

 mixed in it not being an essential part, such as detached epithelium 

 of the gland-vesicles and ducts. 



The development of the pancreas commences with an outgrowth 

 from the posterior wall of the duodenum, and advances onwards, 

 as in the salivary glands, only that the gland-rudiment forms, at 

 first, a more compact mass, and cannot, therefore, be so well 

 observed in its individual parts. 



The investigation of the pancreas presents no difficulties, except that the 

 fat of the epithelial cells of the gland-vesicles disturbs their observation in 

 man; and the pancreas of the lower mammalia (rabbit, or mouse), where 

 there is much less fat, should, therefore, also be studied. The glandules upon 

 the ducts are best seen after the addition of acetic acid. 



Literature. — A. Verneuil, Mem. sur VAnat. de Pancreas, in Oaz. Med., 1851, 

 Nos. 25 and 26. Bernard, Mem. sur le Pancreas, Paris, 1856. 



VII. Of the Spleen. 



§ 165. The spleen is one of the so-called vascular glands, and 

 stands in a certain relation to the renovation of the blood, and 



