146 J- Moore, 



nuclear figures of all, should answer every purpose. Unfortunately, 

 this substance is quite incapable of differentiating the centrosomes in 

 the tissues of the rat, either by itself or in any combination that I 

 can devise. Ordinary Fuchsin has very little power over the centro- 

 somes in the testes of Nematodes, although it brings out the archoplasm 

 and chromatin as strongly as one could wish; — Acid Fuchsin on the 

 other hand stains them readily enough, as the brilliant investigations 

 of 0. Hertwig will show. 



Again, in the case of mammals, we get the best nuclear figures 

 with methyline violet and safranin, but it is quite impossible with 

 these stains alone to demonstrate the centrosomes with any degree of 

 certainty. If, however, we stain the tissues with ordinary Fuchsin 

 and then wash out the diffuse coloration produced with Orange G., 

 the centrosomes are left as clear red bodies at the apices of the 

 spindle figure (Fig. 6 c) ; and finally, if the centrosomes have the same 

 staining capacity as the nuclear microsomes, why was it necessary for 

 Flemming to devise ^) a complicated treatment involving the action of 

 Orange on the joint effect produced by safranin and gentian violet, 

 when either of the two latter would give infinitely better figures? 



We may of course say that the difference between the staining 

 capacity of the centrosomes is due to "a difference in physical state"; 

 but if we do, we are treading on very shaky ground — since most of 

 the substances at present recognised in cells are differentiated solely 

 by their different action when subjected to such micro-chemical 

 agents. ^) 



These facts and considerations debar me from accepting the idea, 

 at any rate for the present, that the centrosomes are merel}^ accen- 

 tuated microsomes. Although, when stained, they appear very much 

 the same colour as the chromosomes, they evidently lack something 

 either in substance or in texture when compared with the mici'osomes, 

 otherwise they would always stain with the simple nuclear stains. 



») Archiv für Mikr. Anat. Bd. XXXVII. p. 686, Footnote. 



-) It may be here remarked that Julin's results seen to have led him to the 

 conclusion that the centrosomes have the same micro-chemical reactions as the 

 para-nuclein. 



