GLANDULAR CELLS OF THE FROG'S PANCREAS 367 



or filaments, i.e., chondriocontes, when the fixation is perfect 

 (figs. 44 to 65, 71 to 74, 80, 81, etc.). They are of even thickness 

 and of smooth contour; local enlargements and the like are usu- 

 ally lacking. Their course may be either straight or curved, 

 undulatory or corkscrew-shaped. When a filament abruptly 

 changes its direction at a certain point, an appearance as if it 

 carried a grain, is often produced; in the same manner, undulatory 

 or corkscrew-shaped mitochondria may appear, on superficial 

 examination, either as filaments carrying granules or as rows of 

 granules. So far as could be seen by most careful observation, 

 however, there were no chondriocontes carrying the so-called 

 plastes, described by some investigators, nor rows of granules 

 and free granules of mitochondrial nature, except in certain lo- 

 cations in the cell (figs. 57 to 66, 71 to 74, 77, etc.). Hoven's 

 ('10, '12) observations on such granules were perhaps made in 

 unsatisfactorily preserved materials. In fact, it will be seen that 

 similar granules on the chondriocontes as well as granules of 

 various sizes disseminated in the cell-body increase more and more 

 as we pass toward the deeper parts of the piece, where the cell 

 structure is usually imperfectly preserved. Mislawsky ('11, 

 '13) and Ciaccio ('13) also claim that the formation of granules 

 is either an artificial or a pathological process. The shape of 

 mitochondria varies to a more or less extent according to the 

 fixatives employed. Osmic acid alone or mixtures containing a 

 great amount of it seem to cause the thickening and shortening 

 of chondriocontes, which, at the same time, take a straighter 

 course (figs. 62 to 64). 



The chondriocontes, as seen in perfectly fixed preparations, 

 are independent; in other words, they neither ramify nor anas- 

 tomose, as described by Hoven ('10, '12), Levi ('12), and others. 

 An appearance of the net formation, as described by Mislawsky 

 ('11, '13), is perhaps due to the interlacement or eventual adhe- 

 sion of chondriocontes. Maximow ('16), also, reached the same 

 conclusion. The occasional occurrence of anastomosis, ramifi- 

 cation, or rings (figs. 41-43) is probably owing to fixation arti- 

 facts of chondriocontes, for we never see such structures in per- 

 fectly preserved portions of the section. On the other hand, I 



