128 THE MITOCHONDRIAL CONSTITtTENTS OF PROTOPLASM. 



other gland-cells. This conception is also in accord with the theory that the mito- 

 chondria play the part of " eclectosomes " (p. 103). 



Favre and Dubreuil (1914, p. 91) have, still more recently, attacked the same 

 problem in plasma cells. Here they find a similar relation between the mitochondria 

 and the "grains de segregation." Where there are many mitochondria there are 

 few "grains de segregation," and vice versa. They make no reference to morpho- 

 logical or chemical transitions between the two. 



Their general conclusion of the participation of mitochondria in the secretory 

 activities of connective-tissue cells is open to criticism along several lines. In the 

 first place, we know next to nothing about the said secretory activities. We can 

 not measure them or obtain any clue to the properties of the secreted substances. 

 Yet we can not say that these cells do not secrete because, in all probability, all 

 cells give off materials into the surrounding fluids. Consequently their state- 

 ments that the secretory activity is high or low must be accepted with caution, 

 for the mere presence of a large number of "grains de segregation" does not suffice. 

 Their increase in number may be due, not to an increase in the rate of their produc- 

 tion, but to a decrease in the rate of their elimination. We may be dealing in some 

 cases with retention pictures. Neither do we know definitely that these "grains 

 de segregation" represent the secretion. So much for the secretion itself and 

 for their statements of variations in its amount,- for their argument is none other 

 than the old one of presence and absence and of reciprocal relations. 



In the second place, investigators will question thek genetic series, particu- 

 larly with reference to the lymphocytes; because if the lymphocytes do not trans- 

 form into the other connective-tissue cells, as they beUeve, there is nothing signifi- 

 cant about their small content of mitochondria as contrasted with the large amount 

 in the connective-tissue cells, wliich they suppose to have assumed the abiUty to 

 secrete. That is to say, they have not established beyond question the steps in 

 their series, in which they claim that there is a relation between the amount of the 

 mitochondria and the secretory activity, the weak link in the chain being the 

 lymphocyte, wliich many people look upon as a fully differentiated blood-cell. 



Lastly, the absence of transition forms between the mitochondria and the 

 "grains de segregation" can not fail to escape attention. None of these inves- 

 tigators claims to have observed them, and we must therefore reserve judgment 

 with regard to the part played by mitochondria in the formation of the "grains 

 de segregation" and in the production of the unknown secretion of connective- 

 tissue cells. 



CILIARY APPARATUS. 



Saguchi (1917, p. 265) has made a careful study of the development of the 

 ciUary apparatus. He describes first an accumulation of mitochondria (chondrio- 

 contes) between the nucleus and distal cell border, a subsequent migration toward 

 the distal cell border and a transformation into rod-Uke corpuscles arranged in rows. 

 These emit, at successive periods, short initial cilia, wliich gradually lengthen until 

 the definitive ciha are formed. He is careful not to assert that there is a chemical 

 transformation of the mitochondrial substance into that of the cilia. 



