GIANT-CELLS OF BONE-MARROW 123 



that is, as it passes to the more complex polymorphonucleated, 

 and ultimately to the polynucleated condition, the bacillary 

 and granular types of mitochondria relatively decrease numeri- 

 cally and the vesicular or annular type increases (compare figs. 

 5 and 7) . 



Since the Kopsch technic preserves the nuclei only poorly, 

 a minute seriation of successive stages cannot be determined. 

 Accordingly, giant-cells, apparently closely similar with respect 

 to nuclear condition, contain in one case predominantly granular 

 mitochondria, in other cases predominantly vesicular forms 

 (figs. 6 to 8). According to the Lewises, in cultures of young 

 connective tissue ring-shaped mitochondria represent a stage 

 in degeneration and are characteristic of the older cells (p. 395). 

 This agrees with my original conclusion with regard to these 

 giant-cells. Duesberg ('20), however, interprets mitochondria 

 of vesicular form (in older spermatids of opossum) as the result 

 of 'defective fixation.' In living cells in teased preparations 

 he could see no vesicles, but only solid granules. He states 

 further that during this particular period of spermogenesis the 

 mitochondria are especially sensitive to the action of fixing 

 reagents, while at the same time exhibiting an increased resist- 

 ance to the dissolving action of acetic acid (p. 64). N. H. 

 Cowdry ('20) finds that in plant cells the form of the mito- 

 chondria varies in the same type of cell without discernible 

 cause, developmental, preservative or pathologic. He says that 

 'it is impossible to find two rootlets, although growing under 

 precisely similar conditions, in which there is not some difference 

 in the mitochondrial contents of cells from similar portions.' 

 He finds 'also that there is much variation in the manner in which 

 mitochondria react to experimental conditions in different parts 

 of the same rootlet and also in rootlets of different stages of 

 growth' (p. 197). Nicholson ('16), on the contrary, records for 

 certain types of neurons of the brain of white mice a fairly specific 

 qualitative difference in the mitochondrial content, as well as a 

 fairly constant variation in form of mitochondria in different 

 parts of the same cell (p. 342). Moreover, in the eosinophilic 

 leucocytes preserved in the marrow fixed with osmic acid, many 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 29, NO. 1 



