[NicHOLLs] SIGNIFICANCE OF "DUST-BODIES" OF THE BLOOD 11 



ment, giving an appearance •which has been aptly compared by Stokes 

 and Wegefarth to the swarming of bees. This swarming motion can 

 be greatly stimulated by the addition to the preparation of an equal 

 quantity of 1 per cent of acetic acid. Whenever a pseudopod is thrown 

 out, the granules quickly make their way into it, carried by a streaming 

 motion of the protoplasm. Again, when a pseudopod is about to be 

 retracted, the movement is initiated by the return of the granules into 

 the main body of the cell. When all have retired, the pseudopod is 

 withdrawn, and the whole process may be repeated in another direction. 

 After a little time, the leucocytes become fixed to the glass slide, so that 

 they are no longer carried about by movements of the plasma. Any 

 pseudopodia which are present, however, remain free^ and wave about 

 in the current. Several times I have seen such pseudopodia, very long 

 and wliip-like, oscillating quickly from side to side, and these may con- 

 tain granules which are placed along the delicate process much like 

 beads upon a string (see Fig. 2). On one occasion, I saw such a 

 pseudopod with tT\'o granules break loose, owing to a collision with a 

 neighbouring cell, and go floating off with a rapid Brownian movement, 

 similar to that of the "Dust-bodies." In another case I saw in the 

 process of contraction of the cytoplasm one or two granules left free, 

 like wreckage left on a beach by the retreating tide. I have, therefore, 

 no doubt that under certain circumstances granules may be set free 

 from the leucocytes, in which case they present exactly the appearance 

 and behaviour of certain of the " Dust-bodies." This must be said, 

 however, that the liberation of the granules, as Just described, is only 

 observed very rarely, and in view of the fact that the number of the 

 " Dust-bodies " is increased in blood which has been kept for some 

 hours quite out of proportion to this freeing of the granules, I have 

 come to the conclusion that comparatively few of the " Dust-bodies " 

 are to be regarded as liberated granulations. To further elucidate this 

 matter, I have endeavoured to ascertain the microchemical and tinctorial 

 peculiarities of the "Dust-bodies." As is well-known, the alpha and 

 epsilon granulations of the white cells have an affinit}^ for acid dyes, 

 such as acid fuchsin and eosin. These stains are commonly used to 

 stain dried blood films, so as to differentiate the various forms of 

 leucocytes. It is obviously impossible to investigate the staining quali- 

 ties of the " Dust-bodies " in dried films, inasmuch as they are extremely 

 minute, and, in the process of smearing the film, many cells are frag- 

 mented so that the microscopic field presents masses of cellular debris. 

 I have, therefore, devised a method of staining the " Dust-bodies " in 

 fresh blood. For this purpose I have used half per cent solutions of 

 Ehrlich's neutrophile stain, or of water-soluble eosin in physiological 

 saline solution. By means of the small platinum loop, before referred to, 



