470 THE LACHRYMAL GLANDS, BY FRANZ BOLL. 



stitial connective-tissue cells join only with the external wall 

 of the alveoli, and never with the capillaries, which do not in 

 any instance possess a membrane corresponding to an adven- 

 titia capillaris. 



Giannuzzi, the discoverer of this lacunar cavitary system in 

 the secreting parenchyma, regards it as a true lymphatic space; 

 that is to say, as standing in direct connection with, and injeet- 

 ible from, real lymphatics, and as analogous with the spaces 

 stated by Ludwig and Tomsa to surround the canaliculi and 

 blood vessels, of the testis, the injection of which can actually 

 be accomplished from the lymphatics of the cord. This, how- 

 ever, has certainly not yet been satisfactorily effected in the 

 case of the above-described space. Numerous attempts failed 

 in consequence of the delicacy of the lymphatics emerging 

 from the glands, and the resistance presented by their valves. 

 Yet appearances are not unfrequently presented in specimens 

 made by simple puncture injections, which at least render it 

 probable that the spaces in the several parenchymatous bodies 

 are in direct communication with true cylindrical lymphatics 

 running in the loose connective tissue of the fissures separating 

 the several parenchymatous bodies. In what mode, however, 

 the cavity situated within the several parenchymatous bodies, 

 and here sharply defined by the external surface of the mem- 

 brana propria and of the blood capillaries, is shut off towards 

 the larger trunks of the excretory ducts and bloodvessels, as 

 well as towards the connective-tissue septa, has not as yet been 

 clearly demonstrated. 



4. THE EXCRETORY DUCTS. The lachrymal ducts are lined 

 by a single layer of low columnar epithelial cells. Where they 

 enter the gland they speedily break up into numerous branches, 

 which have a similar low columnar epithelial lining, and from 

 these again are given off those ducts that Pfliiger has termed 

 " salivary tubes " in the case of the salivary glands, and which 

 may be most appropriately termed lachrymal tubes. Their 

 internal diameter is usually small, and they are lined by elon- 

 gated columnar cells, which are characterized by presenting 

 a very distinct fibrillation at their basal extremity, which 

 Pfliiger has described at great length, and has brought into 



