U KOYAL SOCIETY OF CANADA 



degree quite out of proportion to the amount of liberation of the 

 granules that is observed. 



Another possibility as to the origin of the " Dust-bodies " has yet 

 to be considered, namely, that they may be albuminous particles pre- 

 cipitated from the plasma (7). This was suggested to my mind by the 

 observation which I have frequently confirmed, that the " Dust-bodies " 

 are to be found in great abundance in the fluid which is found at 

 autopsy in the various serous cavities of the body. It is a usual thing 

 to find after death a few drachms of a clear, limpid fluid, like water, 

 in the peritoneal, pericardial, and pleural cavities. This is perhaps 

 a normal condition of things designed to facilitate the movements of 

 the contained organs, or else is an agonal manifestation. In any case, 

 the fluid appears to be identical with the lymph. If a little of such fluid 

 be drawn off with a pipette from the upper portion, relatively few 

 "Dust-bodies" can be found, but in the dependent portion of the 

 cavity they are present in great numbers. Now there are few if any 

 blood cells in such fluid, and it seems hard to believe that such " Dust- 

 bodies " could be the products of the disintegration of cells elsewhere in 

 the body which have been carried to and deposited in the serous sacs. 

 They must either be derived from the breaking down of the lining 

 endothelium of these cavities or be precipitated from the lymph. That 

 this latter mode of origin is possible, and indeed probable, I have been 

 able to demonstrate to my own satisfaction. If one mixes a drop of 

 fresh blood serum, taken on a small platinum loop, with an equal 

 quantity of a four per cent solution of acetic acid, caustic soda, or abso- 

 lute alcohol, a precipitate is thrown down at once. Under the micro- 

 scope this appears in the form of delicate semi-translucent masses or 

 clumps, but with this there is an enormous increase in the number of 

 the "Dust-bodies." These and the smaller portions of the precipitate 

 present marked Brownian movement. This is perhaps best marked 

 when acetic acid is used. The presence of this agent in minute quanti- 

 ties (0.5 per cent) has been noted by Stokes and Wegefarth to increase 

 the activity of the granules within the leucocytes and also that of the 

 free " bodies," an observation which I have repeatedly confirmed. With 

 the other agents mentioned, this is perhaps less marked. By this 

 method it is possible to produce "Dust-bodies" at will. In order to 

 eliminate all possible sources of error, I previously examined the serum 

 under the microscope and noted the number of "Dust-bodies" which 

 were visible in a given field. I used distilled water, which had been 

 boiled just before using, to make thejdilution of the agents mentioned, 

 and then examined such dilutions under the microscope to see that no 

 foreign material was present, which could be mistaken for "Dust- 

 bodies." The admixture of the serum with the reagent was then made 



