398 



THE DIGESTIVE SYSTEM 



With the increased breadth of the basal zone during secretion, there 

 appears in this portion of the cell a structure which has been de- 

 scribed by Nussbaum (Arch. mikr. Anat., 1885) as the Nebenkern, 

 and which has been carefully studied by Mathews (Jour, of Morph., 

 1899). This is a spheroidal basophil body which lies near the nucleus 

 and is frequently surrounded by a clear area of cytoplasm. Its origin 



and function are undetermined 

 and it is possible that several 

 distinct bodies have been in- 

 cluded under the name. Ogata 

 (Arch. f. PhysioL, 1883) con- 

 siders that it is derived from 

 the nucleus by the extrusion 

 of its plasmosome, an opinion 

 which seems to be shared by von 

 Ebner (Kolliker's Handbuch, 

 1902, Ed. iii, 5, 250). The 

 studies of Mathews have shown 

 that at least in certain instances 



FIG. 370.-PANCREATIC ACINUS OF CAT ifc is distinctly fibrillar and sug- 

 CUT TRANSVERSELY NEAR FUNDUS, gest that it may be concerned 



SHOWING THE BASAL (PROZYMOGEN) 

 FILAMENTS OF THE CELLS. 



with the mechanism of secre- 

 tion. It most probably repre- 



The alveoli of the central portions of 

 the cells represent dissolved zymogen sents a post-secretion remnant 



granules. X 1500. 



basal fila- 



of ergastoplasmic 



ments. 



In addition to this fibrillar complex of basophilous substance, there 

 may be seen in appropriately fixed and stained preparations, another 

 group of fibrils, the mitochondria. These can be seen in fresh acinar 

 cells and in tissue preserved in fluids which lack acids (mitochondria are 

 dissolved by acids), when they also give to the basal portion of these 

 cells a striated appearance. These basal bodies have been extensively 

 studied by Bensley (Amer. Jour. Anat., 12, 3, 1911) in the pancreas of 

 the guinea pig, and their independence from the basal filaments of 

 Solger established. Mislawsky also (Arch. mikr. Anat., 81, 4, 1913) 

 has recently studied the mitochondria in the acinar cells of the rabbit's 

 pancreas. He finds no evidence to indicate that they segment into the 

 zymogenic granules. They are described as interstitial elements of the 

 protoplasmic reticulum, more probably connected with the general cell 

 metabolism. There is apparently no good evidence in support of the 



