394 E. V. COWDRY 



cell; Meves ('07, p. 838) that the chains of chondriokontes in the 

 ax's cylinder process and in the adjacent portion of the cytoplasm 

 are converted into neurofibrils; Gerini ('08, p. 182) that they are 

 formed at either pole of the nucleus from minute granules which 

 stain deeply by Cajal's method; and, finally, Hoven ('10. p. 475) 

 asserts that the neurofibrils are generated from a reticulum of 

 mitochondrial filaments in the cytoplasm of the neuroblasts and 

 ganglion cells. 



Most of the work dealing with the development of the cyto- 

 plasmic constituents of the nerve cells of the chick seems to me 

 to be open to criticism on the basis of the following considera- 

 tions : 



(1) Point of view. Goldschmidt's hypothesis ('09, p. 107) that 

 mitochondria belong -to the category of chromidial apparatus 

 (Faure-Fremiet '10, p. 483); Smirnow's conception ('07), am- 

 phfied by Hoven ('10, p. 479), of the similarity of the mitochon- 

 dria and the reticular apparatus; and, lastly, Meves generaliza- 

 tion ('08, p. 845) that the fibrils in various types of cells are 

 developed from mitochondria, forwarded as they were before 

 definite proof was forthcoming, rendered the dissociation of the 

 cytoplasmic constituents more difficult for investigators working 

 on morphogenesis. 



(2) The confusion which has arisen by the application of many 

 ill-chosen terms to a definite and concrete class of cell granulations 

 called 7nitochondria by Benda in 1899. Among these may be men- 

 tioned 'Chondriosomen' (granules), 'Chondriokonten' (thread- 

 like granules), 'Chondriomiten' (granules distributed in rows) and 

 'Chondriom' (the cellular content of chrondiosomes). Meves has 

 devised yet another series, Tlastosomen,' Tlastochondrien' and 

 Tlastoconten.' When one considers in addition the vast array 

 of names applied in the older literature to mitochondria, such 

 as for instance cytomicrosomes, interstitial granules, Flemming's 

 fila, Altmann's bioblasts, fuchsinophile granules; although at the 

 present day we recognize that each of them comprises also many 

 granules which are not mitochondria, so that none of them may 

 be regarded as synonyms for mitochondria, and also the fact 

 that each term is modified more or less depending upon the na- 



