124 H. E. JORDAN 



of the granules appear vesicular (fig. 13) . I come to the tentative 

 conclusion that as these giant-cells progress in development 

 beyond the hemoblast stages bacillary mitochondria give way 

 to granular, and that in the older stages of the polymorphokaryo- 

 cytes the granular mitochondria react to this technic in such a 

 manner as to give the appearance of a vesicle or ring. Appar- 

 ently the less resistant center of the eosinophilic granule, and of 

 the granular mitochondrion, is dissolved or rarefied by the 

 Qsmic acid of this technic. 



The mitochondria qbviously increase enormously in number 

 as the young giant-cells grow in size, but I have seen no indi- 

 cation of the manner of mitochondrial formation. The most 

 obvious conclusion would seem to be that in these cells new 

 mitochondria arise from out of the cytoplasm rather than by 

 segmentation of preexisting mitochondria. Only occasionally 

 are the mitochondria arranged in definite lines, simulating in 

 this condition varicose or segmenting fibrils (fig. 9). 



In certain giant-cells the segregation of the mitochondria 

 within the endoplasm is striking (figs. 5 and 7). In this respect 

 the mitochondria are disposed like the metachromatic granules 

 shown in preparations according to Wright's technic. In these 

 cases there appears a clear, narrow, non-granular exoplasmic 

 layer. However, no evidence appears in my preparations bear- 

 ing on the question of the genetic relation between mitochondria 

 and the metachromatic granules. The number of mitochondria 

 also varies greatly in different cells (compare fig. 7 with figs. 

 10 and 11). 



As regards mitochondria, therefore, the definite result accrues 

 from this study that the hemogenic giant-cells of red bone- 

 marrow are characterized by a type of mitochondria predomi- 

 nantly of the small granular form. 



THE GOLGI APPARATUS 



The sole recorded observation on the internal reticular appa- 

 ratus of Golgi in giant-cells of red bone-marrow is a brief refer- 

 ence by Retzius ('01). Retzius used the bone-maiTow of young 



