THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 127 



GLYCOGEN FORMATION IN THE LIVER. 



Arnold (1908, p. 365^ claims that mitochondria play a part in the origin of 

 glycogen, but does not submit any evidence. Fiessinger and Lyon Caen (1910, 

 p. 454) conclude that glycogen is formed between the mitochondria, not in them. 



GRANULATIONS IN CONNECTIVE-TISSUE CELLS. 



The whole Lyon school, headed by Renaut, look upon cells of the connective- 

 tissue variety as gland-cells, and they have attempted to correlate the mitochondria 

 with the processes of secretion, which they believe to go on in them. They differ 

 from most investigators in including lymphocytes under this heading. 



Renaut and Dubreuil (19066, p. 230) call attention to the following observa- 

 tions: (1) that the perineme (i. e., the mitochondrial apparatus) is rudimentary 

 in young forms like the small rhagiocrine lymphocytes; (2) that it develops more 

 and more in direct measure as the cell becomes older and its secretory activity 

 grows ; (3) that it decreases Uttle by Uttle as the cell ages and its secretory activity 

 declines. In other words, they relate the mitochondria to the act of secretion; 

 but they say nothing about transitions between the mitochondria and the secre- 

 tion granules, which they style "grains de segregation." Tliis is an important 

 omission. 



A few years later Dubreuil (1913, p. 134) brought forward more detailed 

 observations of the same nature, bearing on the same problem. He beUeves that 

 all the connective-tissue cells in the embryo are secreting, and he has found that 

 they all contain abundant mitochondria. In the adult he considers the secreting 

 function to be relegated to the round and mobile connective-tissue cells and to 

 the elasmatocytes, the fixed connective-tissue cells being quiescent. He discov- 

 ered that the mitochondria are very numerous in the former and rare in the latter. 

 He cites his observations on fat-cells as a .second example. While the mitochondria 

 are few in connective-tissue cells destined to undergo fatty metamorphosis, they 

 are enormously augmented in the earlj' stages of differentiation, and, when the cell 

 has accumulated the maximum amount of secretion in the form of fat, another 

 change takes place and the mitochondria disappear almost completely. The cells 

 of the lymph and serous fluids furnish, he believes, still another instance of parallel- 

 ism between the amount of mitochondria and the secretory activity. In direct 

 proportion as they increase in size, departing from the true lymphocyte type, their 

 secretory properties increase; and at the same time the mitochondria also increase 

 and soon form a dense layer about the nucleus. In addition to this, he thinks 

 that young cartilage and bone cells secrete and for this reason contain many more 

 mitochondria than the older ones. Lastly, he has observed that, on inflammation, 

 fixed connective-tissue cells, which he supposes have lost their ability to secrete, 

 begin to secrete again at a very rapid rate; and that, coincident with this, their 

 mitochondria become just as abundant as in the actively secreting connective- 

 tissue cells of the embryo. He admits that a demonstration of the direct trans- 

 formation of mitochondria into products of segregation in large mononuclear cells, 

 connective-tissue cells, cartilage and bone cells, has not been made, but claims that 

 we can nevertheless believe in such a transformation because it occurs in many 



