Sidney Klein 327 



scribed and figured (Fig. &). As early as four hours after feeding, a 

 change in the number and size of the granules may be noticed. They are 

 obviously reduced in number and are somewhat smaller. At six hours the 

 condition represented in Fig. 5 is presented. The cells are longer and 

 narrower and the granules are small, few in number, and occupy the 

 distal segment of the cells only. Indeed, at this stage the cells have 

 assumed very much the same appearance as they present in the animal 

 which is feeding irregularly, although the amount of prozymogen is 

 greater in the six hour stage. At no stage of secretion have I found the 

 fusion of granules into large masses described by Nicolas, if a fixative 

 was employed which was effective in fixing the granules in all parts 

 of the tissue. With some of the fixatives mentioned at the beginning of 

 this paper great differences were found in granules in different cells both 

 in staining power and in form. Very common in these imperfect fixa- 

 tions were the granules composed of a faintly stained central mass with 

 a deeply staining crescent at one border corresponding to the safranino- 

 philous body of Xicolas. I have no doubt that these appearances are 

 entirely due to imperfect fixation, and that the crescent-shaped granules 

 have no existence in the living cell. On the other hand, the different be- 

 havior of granules towards the same fixative even in the same cell indi- 

 cates clearly that some of the granules differ from others either chemi- 

 cally or physically, and it is probable that this difference is due, as 

 Nicolas supposed, to a change in the granule preparatory to its solution 

 and extrusion from the cell as a part of the secretion. 



As regards the prozymogen the experiments did not result in a great 

 change in its amount. It is probable that an equilibrium is established 

 between the rate of production and use of this substance which results in 

 the amount in the cell being kept fairly constant. 



SUMMARY OF EESULTS. 



The results recorded show clearly that the cells of Paneth correspond 

 in their structure and microchemical reactions to the enzyme-producing 

 cells of other granular organs, such, for example, as the cells of the paro- 

 tid gland, the chief of the fundus glands of the stomach, and the cells 

 of the pancreas. 



In common with these cells the cells of Paneth contain granules which 

 do not stain in the specific stains for mucin, such as mucicarmine and 

 muchamatein, and which react like zymogen granules to such stains as 

 iron hematoxylin, neutral gentian and acid rubin. In addition they 

 contain in their basal segment a substance which is distinguished by its 



