GIANT-CELLS OF BONE-MARROW 125 



rabbits and cats. At least in so far as he dealt with the bone- 

 marrow of rabbits, he was almost certainly concerned exclusively 

 with the hemogenic giant-cells. His results may therefore be 

 properly compared with mine for this tissue. 



Retzius used as fixing fluids Rabl's mixture (sublimate-picric- 

 acetic-acid) and Carnoy's fluid. In preparations stained with 

 iron hematoxylin and various counterstains, including eosin, 

 he claims to be able to demonstrate the Golgi apparatus. 



Since Retzius' contribution includes no illustrations, and since 

 the modified Kopsch technic gives a picture very different from 

 that described by Retzius, I repeated Retzius' technic with a 

 view to observing the specific appearance that he interpreted as 

 a Golgi apparatus. 



The condition that seems least likely to represent a fixation 

 artifact, while at the same time corresponding fairly closely 

 to the description of Retzius, appears in the preparations fixed 

 with the Carnoy fluid no. 1 (absolute alcohol 60 cc, chloroform 

 30 cc, glacial acetic acid 10 cc). Rabl's mixture, as also the 

 Carnoy's fluid no, 2, produces results which are obviously exag- 

 gerations of the condition seen in the tissue fixed with the unmodi- 

 fied Carnoy's fluid, and which seem clearly to be fixation alter- 

 ations. As illustrated in figure 12, the Carnoy fluid (no. 1) 

 discloses a collection of anastomosing canals, in general parallel 

 with the surface, and apparently opening onto the periphery. 

 The system, as revealed by changing the level of focus, is rather 

 more complex than could be shown to advantage in the illustra- 

 tion. This system answers to Retzius' description of a structure 

 of 'peculiar canal-like character apparently similar to the tropho- 

 spongium described by Emil Holmgren in spinal ganglion cells.' 

 Influenced, however, by Heidenhain's idea regarding the func- 

 tion of these giant-cells, namely, 'that they serve solely to imbibe 

 and alter proteids taken either from the lymph or the blood 

 stream to be again returned to them' (cited from Retzius), he 

 inclined to interpret this system of canals as 'similar to the 

 secretory canals of gland cells rather than nutritive canals.' 

 He states further that 'these canals of giant-cells appear to be a 

 mechanism for the elimination of products of metabolism of these 



