CHONDRIOSOMES 



SI 



about 24 hollow spherical bodies are formed instead of a ring. These 

 show no evidence of division but are separated into four approximately 

 equal groups by the cell-divisions, each spermatid receiving six or occa- 

 sionally five or seven. ^^ It is not improbable that this regularity of 

 distribution in spermatocytes bears some relation to the definite function 

 performed by the chondriosomal substance in the development of the 

 spermatozoon (p. 218). 



The Function of Chondriosomes. — Our knowledge of chondriosomes 

 is far too incomplete to warrant categorical assertions concerning their 

 function. The literature is not only complicated by conflicting state- 

 ments regarding their observed behavior, but it is further encumbered 

 with a variety of hypotheses, some of which rest on very narrow founda- 



i 



46. — Examples of regular behavior of chondriosomes in cell-division. A-C 

 spermatocyte of Gryllotalpa vulgaris: A, chondriosomal material in cytoplasm; B, first 

 meiotic mitosis, showing chondriosomes (at sides) occupying the achromatic figure with the 

 chromosomes (at center) ; C, stages in the division of a chondriosome. {After Vo'inov, 1916.) 

 D, dividing cell of Geotriton fuscus, showing division of chondriosomes as cell constricts at 

 equator. (After Terni, 1914.) 



tions. The more prominent views on the subject may be outlined as 

 follows. 



Meves in 1908 propounded a general theory according to which all the 

 visible differentiations which develop in different types of cells during 

 ontogenesis were regarded as modifications of the same elementary 

 cytoplasmic constituents, namely, the chondriosomes. These were 

 thought not only to be concerned in the formation of fibrils, plastids, and 

 the like" but also to play an important role in heredity. A close associa- 

 tion was observed between chondriosomes and myofibrils, and it was 

 claimed that the fibrils were actually transformed chondriosomes.^^ 

 A similar claim was made for neurofibrils^^ and other such differentiations. 

 This interpretation of the genesis of fibrils has been adversely criticized, ^° 

 and it now seems probable that, although the chondriosomes may 

 possibly furnish material or cooperate in some other way in the formation 



16 Cf. Sokolow (1913) and Mark and Wyman (1922). 

 " See E. V. Cowdry (1918, p. 102). 



18 Benda (1899), Meves (1907a6, 1909), Duesberg (1909afe). 



19 Meves (1907a), Hoven (1910a), G. Arnold (1912). 



20Heidenhain (1911), Levi (1911, 1916), Gurwitsch (1913), Gaudissart (1913), 

 Lewis (1917), E. V. Cowdry (1914d, 1918), Laguesse (1926), Conklin (1931), and 

 other!.. 



