BLOOD-VESSELS IN OMENTUM OF YOUNG RABBITS. 247 



M. Rauvier has himself taught us that in a transverse 

 section of tendon, for example, the presence of nuclei in a 

 ramifying network does not constitute the network a system 

 of branched cells. In the omentum the question hinges upon 

 our being able to discover the nature of the cells to which the 

 nuclei visible in the appearance we are discussing belong, 

 and this I believe I have been able to do. Even in carmine 

 preparations it is sometimes possible to detect in the walls 

 of the branching figure that beyond the ends of the elong- 

 ated nuclei there is a scant, deeply stained, finely granular 

 substance which narrows to a point, and beyond this is con- 

 tinued into an unstained fibre which differs in its refractive 

 power from the surrounding ' tissue, the distinguishing 

 characters of a spindle-cell being in fact unmistakeable. 

 It is possible in such a preparation to resolve all the nuclei 

 visible into spindle-cells which lie in the wall of the figure 

 The figure itself becomes thus reduced to a ramifying 

 stained, non-nucleated mass, and as faintly stained, narrow 

 prolongations of it can often be traced for a great distance, I 

 must add, of indefinite extent. 



The peculiarity of carmine preparations is that the mass 

 constituting the so-called cellule vaso-formative stains uni- 

 formly in all its breadth, rendering the detection of the 

 spindle-cells very difficult. To show clearly the nature of 

 these appearances we must have recourse to other dyes. 



If the mica square is placed in a half per cent, solution of 

 osmic acid for twenty-four hours and then stained in log- 

 wood solution, we find the appearance is very materially 

 altered. The spindle-cells are deeply stained, the ramifying 

 figure very faintly or not at all. It is sometimes, indeed, 

 distinguished by its being less stained than the surrounding 

 tissue. Instead of a red branching figure containing nuclei 

 in an uncoloured ground, we have in a faintly coloured 

 ground a colourless figure, in the walls of which are deeply 

 stained spindle-cells. The preparation is dotted all over 

 with a great number of large oval nuclei, but these have no 

 special relation to the figure we are discussing. The lymph- 

 cells are stained a uniform deep blue. 



If the mica square is placed in solution of purpurine for 

 twenty-four hours, and is then examined in glycerine, we 

 have preparations that at first sight seem to resemble those 

 coloured by carmine. They differ from them, however, in 

 some important particulars. The branching figure is very 

 faintly stained, the spindle-cell is more deeply stained, and 

 the lymph-cells are conspicuous bodies. Occasionally a 

 lymph-cell, perfectly to be distinguished from the large oval 



