10 ON THE DIFFERENTIAL REACTION TO VITAL DYES EXHIBITED BY 



the larger of these particles can be seen to enter the cell (after adherence to it) by 

 the well-known engulf ment act (phagocytosis), the smallest of them probably do 

 so by virtue of their considerable, even though hindered, powers of diffusion, their 

 penetration being much facilitated by the concentrating mechanism of the segre- 

 gation-apparatus. This is unquestionably the mode of entry of the basic dyes, 

 and the most diffusible of the acid dyes probably fail in the extent to which they 

 give a "vital-staining reaction" when compared with the more colloidal members 

 of the series, not through their lack of power to enter the cell, but through the 

 equal facility with which they leave the same without gaining a segregation or 

 fixation within the cell.' 



Inasmuch as it has been necessary for us to discuss the vital-dye deposits as 

 in the "segregation-apparatus," it is appropriate to indicate briefly, now, the lines 

 of evidence which have led us to this view and to discuss other conceptions of the 

 nature of the vital-dye bodies. Both Fischel and Goldmann, who have furnished 

 important explorations in this field, and Arnold, whose meticulous records occupy 

 the endeavor of a lifetime, have championed the view that with vital dyes, cell organs, 

 pre-existing but less clearly seen, are electively exposed to view. We believe we 

 can nullify the " preformed-structure " argument speedily as far as it relates to the 

 dye granules produced by acid-azo dyes. Modern c} r tological researches, both 

 with fixed and with living material, have acquainted us too accurately with the 

 cytoplasmic structures or cell organs of the connective-tissue cells for us to have 

 overlooked the pronounced structures represented by the dj'e granules were they 

 present in normal cells. We are acquainted with the centriolar apparatus, the 

 mitochondria, and the "vacuoles de segregation" of Renaut (the normal segrega- 

 tion-apparatus). In the macrophages the dye deposits need never be confused with 

 the first two of these cell organs and usually greatly exceed the normal limits set 

 for the third. 



In conformity with Renaut and Dubreuil (see also M. R. and W. H. Lewis), 

 we have found that the normal segregation-apparatus of macrophages is electively 

 displayed by neutral-red solutions (1: 10,000). The dimensions and extent of this 

 system are subject to considerable variation, but under no circumstances does it 

 approach the extent attained under acute dosage with any of the benzidine dyes 

 (fig. 12). Most of the dye structures, consequently, must be interpreted as new 

 formations, a fact which receives all the convincing proof one can desire in cases 

 where an identical cell can be watched in its relation to the dye, e. g., the migratory 

 macrophage cells at the periphery of transparent tissue cultures or in the tail of 

 amphibian larva?, where many of the dye deposits can be seen in the act of origin 

 de novo. 1 The "preformed-structure" conception, indeed, could hardly give us 

 serious concern were it not for the astonishing paper written by Tschaschin, of 

 Maximow's laboratory, the keynote of which is his attempted recognition of all 

 vital-dye structures as mitochondrial derivatives or actual mitochondria, a view 



1 An even better instance id furnished by Clark's description of the large juxtanuclear accumulation of dye globules in 

 the lymphatic endothelial cells of the tail of frog larva; where previously these certainly did not exist. 



