THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 121 



ments which he calls "plastes," and which stain like the mitochondria and secre- 

 tion granules with iron hematoxylin, crystal violet, and acid fuchsin. These, he 

 believes, change into secretion granules, since he has observed all stages of transi- 

 tion between the two. He is of the opinion (contrary to Regaud) that we are here 

 deahng with an actual transformation of mitochondrial material. 



Mislawsky (1911a; 19116, p. 505), however, on the basis of very similar ob- 

 servations, finds no evidence of the direct transformation of mitochondria into 

 secretion granulations. Schultze (19116, p. 258) has also studied the mitochon- 

 dria and zymogen granules in the frog, but does not commit himself regarding 

 their genetic relationship. Champy (1911, p. 122) experimented with secretin and 

 found that intermediary forms between mitochondria and secretion granules are 

 more numerous during secretory activity. Laguesse (1911, p. 277) maintains 

 that his ergastidions (mitochondria) play the part of elaborators in the produc- 

 tion of pancreatic zymogen. CI. Arnold (19126, p. 268) claims that the zymogen 

 gramdes are formed through a maturation of mitochondria, and Chaves (1915, 

 p. 67) speaks of a physiological transformation. 



Key (1916, p. 215) has experimented with the pancreas of the toad. He 

 stimulated the gland by the injection of pancreatic secretion in some cases and of 

 pilocarpin in others. In some experiments the injections were repeated at regular 

 intervals for several days. He found that while this caused a discharge of zymogen 

 granules, the mitochondria were not exhausted, but in some cases seemed actually 

 to increase in length. He was unable to detect any difference between certain 

 bleb-like swellings, which mitochondria possess in almost all secreting cells, and 

 the other parts of the mitochondrial filaments, and he concluded from this that 

 the blebs do not contain zymogen granules. Furthermore, the absence of reciprocal 

 changes in the amount of mitochondria with variations in the cytoplasmic content 

 of zymogen granules led him to believe that the zymogen granules are not formed 

 directly from the mitochondria. 



Scott (1916, p. 249), working in this laboratory, studied the effect of experi- 

 mental phosphorus poisoning upon the pancreas of the mouse. He discovered 

 that slight poisoning brings about a change in the mitochondria only, which lose 

 their bleb-like swellings and their filamentous shape. The nucleus and zymogen 

 granules show no changes. The interesting thing is that in a mild case of this sort 

 the formation of zymogen is not interfered with. Indeed, in much more severe 

 intoxications unmistakable evidences of further formation of zymogen granules 

 are seen. Whole cells are frequently found crowded with them. This means that 

 the mitochondria do not participate through their bleb-like swellings in the produc- 

 tion of zymogen, because zymogen continues to be formed long after these swellings 

 disappear. It can not come from the swellings, because there is none. This is 

 another strong blow to the doctrine that the mitochondria transform into secretion 

 granulations. 



URINARY SECRETION. 



The question of the relationship between changes in the mitochondria and 

 variations in urinary secretion is a difficult one. It is complicated by the presence 



