306 FERNANDUS PAYNE 



somen, chondriosomen, etc.), I have used the original term pro- 

 posed by Benda. 



Benda's conclusions have been supported, in the main, by the 

 researches of Meves, Duesberg and numerous other workers. 

 These workers have also added that the mitochondria are geneti- 

 cally continuous and that they differentiate during embryonic 

 development into myofibrils, neurofibrils and various other filar 

 structures. Opposed to these views are those of Goldschmidt, 

 Popoff, Buchner, Wassilieff, Jordan and others, who maintain 

 that the mitochondria are only temporary structures appearing 

 in the cytoplasm, and that they are of nuclear origin. They 

 homologise these bodies with the chromidia of Hertwig. Many 

 differences in respect to behavior and other details have also 

 been described by these two schools. Goldschmidt later ('09) 

 admits that in embryonic cells mitochondria may differentiate 

 into fibrils. 



' Schaxel, in a series of papers ('09, '10, '11 and '12), describes 

 two types of granules in the cytoplasm, one of nuclear origin, 

 the chromidia, and the other of cytoplasmic origin, the mito- 

 chondria. The chromidia, according to this author, are used up 

 in differentiation, while the mitochondria are continuous cell 

 elements. These observations might lead us to believe that 

 different workers have seen different things and described them 

 as the same thing. 



( Beckwith ('14) has given Schaxel's conclusions a thorough 

 test in a study of the plasma-structure in the egg of Hydractinia 

 echinata. She has employed a wide variety of fixing reagents 

 and stains. Besides the yolk-spheres and oily bodies, she finds 

 two types of granules, one which she calls pseudochromatin 

 granules (perhaps the chromidia of Schaxel) and the other mito- 

 chondria. The pseudochromatin granules appear early in the 

 growth period and transform into yolk. They arise in the cyto- 

 plasm and are not of nuclear origin. The mitochondria do not 

 appear until the yolk is well formed. When they make their 

 first appearance they are scattered throughout the cytoplasm 

 and hence, as the author believes, cannot be of direct nuclear 

 origin. By centrifuging the mature eggs she can cause the mito- 



