268 
George Arnold 
But it will be of interest to point out that tliey are easily distinguisked 
in one particular from tke cells of tke alveoli, by the nature of tkeir chon- 
driosome, wkich is composed of very fine granules, ehondriokonts being 
altogether absent (Fig. 11). 
Thev are also mueh smaller than the alveolar cells, and tkeir cyto- 
plasmie surfaces are very ill defined, so mueh so as to suggest a syncytiuni. 
The centroacinar cells, wliich are the continuations into tke lumen of 
the tubules, of tke cells lining the efferent ducts, contain botk raitochondria 
and ehondriokonts, chieflv the latter, and mav possibly aid in the produc- 
tion of accessory substances in the pancreas secretion. 
I have not seen any mitoses in the alveolar cells, altkough in the 
pancreas of the rabbit they are said to be plentiful. (Bizzozero and 
Vassale 1885.) 
Conelusions. 
The cells of the alveoli of the pancreas contain ckondriosomes made 
up of mitochondria and chondi'iokonts. From these, especially the former, 
granules are given off which eventually mature into true zymogen granules. 
The chondriosome is not of nuclear origin, but is a separate and permanent 
organ of the cell, and confined to the eytoplasm. 
Besides the zymogen granides and the ehondriosomes, a certain and 
small proportion of the alveolar cells contain fine granules, which are 
distributed througli both the inner and outer zones of the cells. They are 
basophile, but can be demonstrated by prolonged staining in acid dyes, 
after acetic ac-id fixation. Their fimc-tion has not been ascertained in these 
investigations. 
Bibliography, 
Arxold, G. 1911. On the condition of the Epidermal fibrils in Epithehoma. Quart, 
journal. Mic. Sc. 
Bizzozero, G. and Vassale, G. 1885. Über den Verbrauch der Drüsenzellen der 
Säugetiere in erwachsenen Tieren. Med. Centralblatt. 
Bütschli, 0. 1871. Vorläufige Mitteilung über Bau und Entwicklung der Samen- 
fäden bei Insekten und Crustaceen. Zeitschr. f. wiss. Zool. Bd. XXI. 
Champy, C. 1909. A propos des mitochondries des cellules glandulaires et des cellules 
renales. C. R. Soc. Biol. Paris. Tom. LXVI. 
Duesberg, J. 1910a. Sur la continuite des clements mitochondriaux des cellules 
sexuelles et des ehondriosomes des cellules embryonnaires. Anat. Anz. 
Bd. XXXV. 
1910b. Les ehondriosomes des cellules embryonnaires du poulet, et leur röle 
dans la genese des myofibrilles, avec quelques observations sur le developpe- 
ment des fibres musculaires striees. Arch. f. Zellforschung. Bd. IV. 
