THE TWO GREAT GROUPS OF CONNECTIVE-TISSUE CELLS. 11 



which, surprisingly, has not been received with disfavor by some able investigators 

 (Kiyono, Maximow). Tschaschin's line of proof for such a claim is singularly 

 uncritical and consists essentially in a mere analogy between the picture furnished 

 by methods for demonstrating the mitochondria in fixed preparations (unfor- 

 tunately not highly specific) and the picture furnished by the minute, frequently 

 linear, fibroblastic deposits. If this fact obtains for the fibroblasts (*. e., the de- 

 position of the dye on the mitochondria), reasons Tschaschin, then it also obtains 

 for the macrophages, and the dye bodies here are merely transformed mitochondria. 

 We will take up the confusion which has obtained in the case of the fibroblasts 

 at a later point in this paper. As regards the macrophages, aside from the fact 

 that these cells normally possess a segregation-apparatus which, though small when 

 compared with the "dye bodies," is at least nearer them in morphological charac- 

 teristics than the mitochondrial system, there is also the clearly demonstrated fact, 

 which Tschaschin overlooked, of the presence of a normal mitochondrial content 

 in vitally stained macrophages. There is, indeed, no method which can equal in 

 exquisite electiveness for the demonstration of mitochondria the supravital applica- 

 tion of janus green B in strengths which vary from 1:100,000 to 1:10,000, but 

 do not exceed the latter. Neither the iron hematoxylin, the fuchsin, nor the 

 alizarine methods have in our hands furnished as satisfactory data as have studies 

 on fresh tissue. Worked out in this way, the mitochondria 1 of the connective-tissue 

 macrophages are seen to consist invariably of a series of granules, rods, and thread- 

 lets scattered throughout the protoplasm between the small vacuoles of the normal 

 vacuolar-apparatus, tending perhaps to be somewhat more frequent in the vicinity 

 of the nuclear membrane (fig. 14). No significant departure from this picture 

 occurs in the case of fully laden vitally stained cells (figs. 15, 17, 19). The mito- 

 chondria have not disappeared in these cells, though they are often forced to occupy 

 squeezed-in positions between large vacuoles which are almost contiguous and badly 

 crowd the cytoplasm. These facts, stated by one of us in a previous preliminary 

 communication, are, however, not always easy to demonstrate, but we believe we 

 have disclosed the reason for this in the fact that if counterstaining with janus 

 green be attempted while the tissue fluids are still full of the azo dye, a chemical 

 precipitation between the acid and basic dyestuffs prevents the janus dye from 

 exercising its specific effect unless it be employed in fairly high concentrations 

 (1:5,000) and be several times renewed. In spite of the work of Dubreuil, Guil- 

 lieremond, Azzi, and others on the share which the mitochondria take in the mo- 

 bilization of natural pigments, glycogen, and fat (conceptions which the Lewises 

 were unable to confirm), we must also range ourselves with the latter observers 

 in so far as the deposition of acid dyes within these cells is concerned, for we have 

 at no time found justification for Tschaschin's description of a modification of the 

 mitochondria by virtue of their assumption of a dye-storage function. 



The conception that the "dye bodies" are actual accumulations of vital dye in a 

 partly hypertrophied, partly newly formed segregation-apparatus devised by the cell 



1 We aee no reason to enrich the terminology by the employment, as some do, of special designations for these structures 

 in accordance merely with their granular, bacillus-like, or thread-like form. 



