X-BODIES AS ARTEFACTS. 423 



A blood smear was stained with Wright's stain and showed many brightly 

 colored X-bodies of various sizes. Several large ones were located with the 

 vernier scale of the mechanical stage. The slide was then removed and scrubbed 

 with water and gauze. On again bringing the located areas under the lens no 

 blood corpuscles could be seen but the X-bodies were still there and unchanged 

 in appearance except that the coloration was less intense. The slide was again 

 removed, scrubbed with alcohol, and replaced beneath the lens. The identical 

 X-bodies were present in the same locations as before, but all trace of the stain 

 had been removed from them. 



If a clean new slide containing no specimen is stained in the usual 

 manner with Wright's stain, and the stain-film is then rubbed off with 

 dry gauze or with xylol, X-bodies, still showing coloration, may be found. 

 This fact suggests that the objects named X-bodies in most instances 

 may be due to minute portions of the stain being retained mechanically 

 in microscopic pits in the glass. Usually, the X-bodies are seen to be 

 at a lower level than the blood corpuscles on a slide. We rarely have 

 found instances where they appeared to be above the corpuscles and the 

 edge seemed to overlap a red cell. Such an appearance could hardly 

 have been due to a pit, but might be caused by a minute scale of glass 

 on the surface of the slide, which would entangle the stain and beneath 

 which the edge of a corpuscle could slip. The slide on which this over- 

 lapping was noted is the one described in the preceding paragraph and 

 the X-bodies which appeared to have the edges slightly overlying red 

 cells were the ones which remained unchanged in location after repeated 

 scrubbing. 



Photomicrographs of these bodies are appended. The photographs 

 were made by Mr. Charles Martin of the Bureau of Science, to whom we 

 desire to express our obligation. The magnification in all cases is 1,000 

 diameters. The first three figures are photographs of X-bodies found 

 on a slide containing a smear of normal human blood, while the last 

 three are of bodies that were found on a glass slide containing no specimen 

 of any kind, but which had been stained with Wright's stain and the 

 dry stain-film then rubbed off with a piece of gauze. The bodies were 

 very numerous on these slides, a number being present in nearly every 

 field, but it is almost impossible to procure good photographs of more 

 than one or two on a single negative owing to the difficulty of obtaining 

 an accurate focus on several of them at the same time. 



REFERENCES. 



(1) Balfoub, a. X-bodies in Human Blood. Lancet, London (1911), 1, 29.5. 



(2) HoKROCKS, W. H. AND HowELL, H. A. L. X-bodies found in Human Beings 



and Animals. Journ. Roy. Army Med. Corps (1908), 10, 451. 



