44 ON THE DIFFERENTIAL REACTION TO VITAL DYES EXHIBITED BY 



color from their solution color, whether in the test-tube, "thread bodies," or 

 vacuolar-apparatus of cells (fig. 77). The filar structures constitute much more 

 faithful copies of filiform mitochondria than of vacuoles, and the feasibility of 

 separating them from the mitochondria must now be entered into. We may re- 

 hearse some of their characteristics which have induced us to take the view we have 

 presented. 



1. They are actually connected with part of the segregation-apparatus and in 

 early stages of their formation transition stages between typical vesicles of the 

 segregation-apparatus and these filar structures can be seen. 



2. In common with the segregation-apparatus, they stain electively with neu- 

 tral red. 



3. They are not stained electively by any of the mitochondrial methods. 



4. They do not undergo morphological alterations post-mortem, even after 

 many hours' standing. 



The intensity of the vital color in the filar bodies is never very great. This is 

 all the more remarkable since they are most abundant where conditions of severe 

 dosage of the cell have ensued, and it may hence be thought that they represent an 

 unusual stimulation effect of these cells and that they possibly stand in some ob- 

 scure relation to the fiber-forming proclivities of the same elements. That they are 

 not collagenous fibers is evident by their failure to stain bj r any of the tinctorial 

 methods for these structures, even though none of such methods is highly elective, 

 for by all methods which deeply stain the extracellular collagenous fibrils in their 

 immediate neighborhood these intracellular "threads" remain untinged. That 

 they may be peculiar degeneration products, resulting from protoplasmic injury 

 due to the direct effects of the stain, is suggested by the discovery of Bachmann 

 (1912) that soaps, for instance, may be precipitated in this peculiar filar form. 

 The structures do not, however, give any of the reactions of soaps or lipoids, and 

 we are unfortunately still without a satisfactory clue as to their significance. The 

 outstanding fact of importance to our argument, however, has been determined — 

 their relation to the segregation-apparatus, not to the mitochondrial system of the 

 fibroblastic cells. 



It is appropriate, lastly, for us to refer to the light which these investigations 

 shed on the question of cell specificit)' in the connective tissues, especially in 

 view of the fact that where this question has been most carefully studied — in 

 the histology of aseptic inflammation, wound-healing, and tissue cultures — various 

 hypotheses and supposed facts of cell transformation have been advanced. Nothing 

 which we have seen leads us to the view that these fundamental cell tj r pes are not 

 constantly, even under the most diverse conditions, maintained. 1 Though we have 

 described great divergencies in the type of staining displayed by both the macro- 



1 Such a statement ia indeed quite different from that which concerns the lymphocytic origin of the macrophage or 

 polyblastic cells and (or which evidence has been brought forward by many of the special students in this field. We have 



not given the lutn-r matter our attention, out studies carried out in this laboratory on the mononuclear blood-cells indicate 

 that a Begregation-apparatus can be clearly demonstrated in these ceils, though there is general recognition that their inges- 

 tion of azo dyestufl's is forbidden as long as they are in the blood or lymph stream. 



