ORGANS OF THE BODY. 



461 



We have already referred (p. 350, fig. 339) to a network of fine 

 secreting tubules or canaliculi, which have been met with in the acini of 

 many racemose glands. These are also to be found in the submaxil- 

 lary glands (Pfluger, Ewald, and others). Even uninjected, they can 

 be recognised as a network of clear, somewhat lustrous, streaks of 

 0-002-0-003 mm. in diameter. 



How far a recently observed connective-tissue reticulum (Boll), which 

 traverses the acinus, has anything to say to these secretion tubules, or is 

 connected with the wall cells of the membrana propria, are points which 

 require closer investigation. 



The walls of the excretory duct are made up of connective-tissue. A 

 thin layer of muscular cells, difficult of . recognition, has been stated by 

 Koelliker to occur here ; these have not, however, been found by others 

 (Eberth, Henle). The epithelial lining consists of a single layer of 

 cylinder cells (d), in whose bodies we may recognise distinct and per- 

 sistent longitudinal markings (Pfluger) underneath the nucleus. 



The vascular networks are, as in most racemose glands, round. The 

 capillaries lie loosely about the glandular vesicles, while their tubes of 

 supply and overflow accompany the ramifications of the ducts. 



The recent investigations of Gianuzzi have made us acquainted with 

 the lymphatics of the salivary glands of the dog. Here they appear as 

 clefts in the interstitial connective-tissue between the lobuli and vesicles, 

 as well as around the lobes of the organ. They are stated, also, to 



Tiff. 444 Mode of termination of the nerves in the snbm axillary gland of the rabbit, after 

 Pfliigtr. In I. and IT. the nerves penetrate into the gland vesicles, and end between the cells 

 of the latter. In III. the termination of a nerve fibre in the nucleus of a gland cell is 

 observed. ' IV. the same, with a "ganglion cell." 



ensheath the venous and arterial twigs before becoming developed into 

 regular lymphatic vessels. 



The mode of termination of the nerves of the submaxillary gland is 

 very remarkable and important, though not, perhaps, in some cases 

 ascertained beyond all doubt. After some earlier studies by Krause, 

 Reich, and Schluter, the point was taken up and pursued with much 

 vigour by that excellent observer, Pfluger, taking the rabbit as subject 



