[NicnoLLs] SIGNIFICANCE OF " DUST-BODIES OF THE BLOOD 17 



SO, this is not the result of an active discharge, or, in other words, an 

 evidence of positive chemotaxis, but a sign of degeneration of the cell 

 protoplasm. Stokes and Wegefarth themselves did not prove that, on 

 the addition of bacteria to fresh blood, there was any attraction of the 

 bacilli for the leucocytic granulations, or any discharge of the latter. 

 The presence of numerous eosinophile free granules in stained prepara- 

 tions of blood proves nothing, since in the process of smearing the films 

 some of the leucocytes are inevitably destroyed by the pressure, and 

 their granules liberated, so that this introduces a source of error into 

 the calculation. Again, as we have seen, the majority of the '"' Dust- 

 bodies " present a different appearance from that of the leucocytic 

 granulations, some having the colouration of the red corpuscles, others 

 being colourless, and only a few, as our staining method has shewn, 

 having the tinctorial peculiarities of the neutrophile and eosinophile 

 granulations. The '* Dust-bodies " are much more readily accounted 

 for in other ways, namely, that they are in the main fragments of red 

 and white cells, or particles precipitated from the plasma. Even were 

 it true that the " Dust-bodies " are in every instance liberated leucocytic 

 granulations, the theory advanced by Stokes and Wegefarth, that the 

 bactericidal properties of the serum are due to the presence of these 

 granules, appears to me to be too mechanical. The theory is simple, 

 too simple, and, moreover, must be regarded as not proven. We are 

 realizing more and more in the light of the multitudinous investigations 

 into the question of immunity, which are being undertaken at the 

 present time, that the subject is one of the most complex in the domain 

 of pathology. 



After many years of conflict between the " Cellularists," on the 

 one hand, and the " Humouralists," on the other, it may be said that 

 the general consensus of opinion among pathologists is that immunity 

 is the result of several correlated factors, principal among which are 

 the phagocytic properties of the leucocytes, notably the neutrophilic, 

 and of the endothelial cells. The phagocytic theory of Metclmikoff, 

 however, is not given the supreme importance which that distinguished 

 investigator has so ably and persistently claimed for it. That 

 leucocytosis is not everything in the fight against infective disease is 

 very clear, for while it is true that in the majority of infective fevers 

 there is a leucocytosis present in the blood, in certain of them, notably, 

 typhoid, there is actually a leucopenia, at least in severe cases, while 

 in others, as in miliary tuberculosis, measles, typhus, and influenza, 

 there is at most an insignificant degree of leucocytosis. Again, we 

 have the important clinical fact that the generalized leucocytosis arti- 

 ficially induced by the injection of such substances as pilocarpin and 



Sec. IV., 1805. 2. 



