GIANT-CELLS OF BONE-MARROW 127 



in the giant-cells of the red bone-marrow (figs. 5 and 7). I 

 therefore feel justified in concluding that a structure, entirely 

 different from that described by Retzius, and agreeing in essential 

 particulars with the reticular apparatus of Golgi described in 

 many other cells, occurs typically in these giant-cells of red 

 marrow. In short, the technic employed by Retzius does not 

 reveal the Golgi apparatus, but does disclose a system of anasto- 

 mosing canals that may correspond to what Holmgren has 

 described as a trophospongium; but which seem to me, at least 

 in this tissue, to be of the nature of a fixation artifact. 



The conception that I have acquired of this 'canalicular appa- 

 ratus' in these giant-cells of my preparations fixed in Carnoy's 

 fluid is that of a result produced by a condensation (coagulation) 

 of the cytoplasm along certain planes, leaving thus an irregular 

 system of intervening layers of more fluid substances simulating 

 canals. In this field of cytology it is especially unsafe to make 

 unquahfied statements, and I would not be understood to even 

 intimate that all so-called trophospongium and canalicular 

 apparatus is artificial, either the result of fixation or temperature 

 changes. But I feel quite in accord with Duesberg's ('20) con- 

 clusion that the closed, locahzed Golgi apparatus is a structure 

 distinct from the diffuse canalicular apparatus, opening at 

 certain points on the periphery, commonly described as Holm- 

 gren's trophospongium, in spite of Holmgren's ('14) insistence 

 that these two structures are one and the same thing. At any 

 rate, in these giant-cells the canalicular apparatus revealed by 

 the Carnoy's fluid, and first described by Retzius, has no direct 

 relation to the much smaller and sharply localized network as 

 revealed by the Kopsch technic. Moreover, this network, which 

 I am designating as the Golgi apparatus, consists, as revealed 

 after the osmic-acid treatment, of solid elements, not of canals. 



The Golgi apparatus of the hemogenic series of giant-cells 

 appears already in the hemoblasts as a closed loop of somewhat 

 irregular form, closely applied to the surface of the centrosphere 

 (figs. 1 to 4). I have not succeeded, as I had hoped to do, 

 in tracing the detailed steps of its development concomitant 

 with the assumption of the polymorphonucleated and the multi- 



