FOURTEENTH LECTURE. 



PANCREAS AND LIVER. 



We have still left the two largest glandular organs of the 

 digestive apparatus, the pancreas and liver. We shall soon 

 finish the pancreas ; the liver, on the contrary, requires a more 

 accurate discussion, in consequence of its peculiarities. 



The pancreas is an enormous racemose structure. It re- 

 minds one of the salivary glands. The rounded acini meas- 

 ure 0.06 to O.09 mm. The membrana propria is likewise 

 said to have flat stellate cells. The rounded vascular net- 

 work was represented in our Fig. 127. The lymphatics re- 

 quire still more accurate investigation. 



The gland vesicles are lined with indistinctly separated, very- 

 granular cubical cells. In the adult rabbit the latter show 

 fatty molecules in their interior, that is in the parts turned to- 

 wards the lumen. The middle and external portions remain 

 transparent. Between them appears the net work of finest 

 secretory tubes, already familiar to us from Fig. 125 (Sa- 

 viotti). 



The thin-walled excretory duct of the human pancreas 

 contains no muscular elements. Below, it presents mucous 

 glandules. 



It is covered by a low cylindrical epithelium. If followed, 

 in animals, into the gland, these cells are found to become 

 more and more flat in the branches. Finally, in the gland 

 vesicles themselves, we meet with thoroughly flattened ele- 

 ments, reminding us of the endothelia of the vessels. These 

 are the so-called " centro-acinary " cells (Langerhans), which 

 are found widely extended, not only in the pancreas, but also 

 in the parotid. 



The character of the gland cells in a quiescent and active 

 condition requires further investigation. 



