Guilliermond - Atkinson 



— 92 — 



Cytoplasm 



search (1912-1923), as well as by that of FRIEDRICHS (1923), that 

 the meristem of the bud of Elodea canadensis does not contain 

 chloroplasts. This is contrary to the findings of NOACK, whose 

 error can only be explained by supposing that in his preparations 

 he confused tissues already differentiated and containing chloro- 

 phyll, with the meristem. It has been proved, besides, that among 

 the elements which constitute the chondriome of meristematic cells 

 in the phanerogams, it is impossible to distinguish those which will 

 later become plastids, from those which will remain chondrio- 

 somes. Both have the same shapes and histochemical character- 

 istics. Cytological work on animals (Levi), as we have said, has 

 established the fact that the chondriosomes are indeed permanent 

 and clearly characterized elements of the cytoplasm. This is dem- 

 onstrated, furthermore, by the research that we have done on the 

 Saprolegniaceae, in which the absence of plastids makes this study 



more easy than in chlorophyll-bearing 

 plants, and in which we have been 

 able to follow the chondriome in liv- 

 ing material during the entire de- 

 velopment of these fungi. It is there- 

 fore not possible, for the time being, 

 to consider the chondriosomes as dis- 

 similar elements, or as products of 

 cellular metabolism (Allmantes). 

 The theory of ARTHUR Meyer, who 

 labels the chondriosomes Allinantes, 

 has never been verified, and is today 

 definitely invalidated. 



It has not been confirmed, either, 

 that the plastids and the chondrio- 

 somes of embryonic cells of phanero- 

 gams can be differentiated by their 

 dimensions, as was thought by MoT- 

 tier who, without doubt, observed 

 only cells already in the process of 

 differentiation. Furthermore, our 

 research has shown that the chondri- 

 osomes which are not transformed into plastids are in no wise 

 exclusively shaped as granules, as Meves believed. It sometimes 

 happens, on the contrary, that in embryonic cells, the chondriosomes 

 exist as chondrioconts, whereas the plastids are represented by 

 mitochondria. This is so much the case, that when the chondrio- 

 somes appear as granules in meristematic cells, they almost always 

 have the appearance of typical chondrioconts after the differentia- 

 tion of the plastids has taken place, as in the leaves of Elodea 

 canadensis. Therefore they are obviously chondriosomes. (Figs. 

 57, 58). 



There is no basis, on the other hand, for the opinion of Weier, 

 for if it is true that the plastids are blackened by osmic impregna- 

 tion because of their lipide constitution, it is also true that the 



Fig. CO. — SimilaritV of the chon- 



diionio in A. tho basidium of Apuricus 



camiHstris; B, the ascus of Pustularia 



vesiculosa: C, frog's liver; D, frog's 



kidney. Kcgnud's method (C, D, drawn 



from preparations of Professor Pou- 



CAKD). 



