[nicholls] significance OF "DUST-BODIES" OF THE BLOOD 7 



Mûller, is extremely small, looking like a particle of dust dancing up 

 and down ia the field, so minute iudeed that it would probably be over- 

 looked by anyone whose attention had not been specially called to it. 

 Moreover, prolonged search generally reveals the fact that in the plasma 

 are similar bodies, still more minute; in fact, all but invisible, jWhich 

 were at first unobserved. 



These fine particles can usually be found ia all parts of the pre- 

 paration. As. a rule, they are most frequently to be observed in the 

 neighbourhood of the red corpuscles, while they are comparatively rare 

 about the leucocytes. They are constantly present, but their numbers 

 seem to vary considerably in different cases, in different persons, and 

 in the same individual at different times. They appear, for instance, 

 to be more numerous after a meal. Their shape also varies. In the 

 case of the very minute forms it is, of course, impossible to determine 

 this point with any degree of accuracy. The larger " dust-bodies " 

 are irregular, roughly globular, pear-shaped, coccoid, or like rods. 

 Sometimes they are in pairs or chains, or the individual elements are 

 joined together by delicate strands. Fig. I. (not drawn to scale) will 

 give a good idea of some of the forms seen. 



Considerable differences in colour also exist. The more minute 

 forms, so far as can be determined, are devoid of colour. Here and 

 there, however, certain of the medium-sized bodies present a distinct 

 rose-pink colouration, as if they contained hsemoglobin. The larger, 

 globular forms, and the red-shaped types, have frequently the peculiar 

 yellowish-green appearance, so characteristic of the red corpuscles in 

 fresh preparations, when seen in a thin film. 



When first observing the " dust-bodies,'^ one might be apt to cod- 

 clude that they were in active motion. They dance very briskly up and 

 down, with a sort of trembling motion, somewhat quicker than that mani- 

 fested by most non-motile bacteria. Some observers have concluded 

 that they are endowed with independent motility. This is undoubtedly 

 a difficult point to settle beyond quibble, as it is a matter of observation 

 into which the personal element enters somewhat largely. I am, 

 however, strongly of the impression that the granules are possessed 

 merely of molecular movement, due to currents of diffusion, and similar 

 to that possessed by minute bodies in general. When they change their 

 position, as they sometimes do, it is probably due to the action of cur- 

 rents in the blood serum, which are undoubtedly present even when 

 the corpuscles are stationary. Anything of the nature of cilia I have 

 never observed. 



On due consideration of the possible sources of origin of these little 

 bodies, it is foimd at once that the problem is somewhat complicated. 



