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The Vacuolation of the Blood-platelets : an Experimental Proof 

 of their Cellular Nature. 

 By H. C. Boss, late Surgeon Boyal Navy. 



(Communicated by Prof. C. S. Sherrington, F.B.S. Beceived May 12, 1909.) 



On July 27, 1907, a paper appeared in the ' Lancet ' by Bonald Boss, 

 S. Moore, and C. E. "Walker, entitled " A New Microscopical Diagnostic 

 Method and some Simple Methods for Staining Liquid Blood." It described 

 new methods for the staining of blood-cells in vitro — notably the agar-jelly 

 method — by mixing polychrome methylene blue with agar and preparing a 

 film : blood-cells spread upon this will absorb the stain, and if the jelly is 

 suitably prepared the different morphological elements of the cells can be 

 readily distinguished. It also described how the leucocytes, after they had 

 been resting on the jelly for a short time, developed bright red spots in their 

 cytoplasm ; and it was suggested that the spots might be centrosomes. 



The spots appear as bright scarlet points, and resemble closely what one 

 would imagine that centrosomes would look like if they could be seen in 

 polymorphonuclear leucocytes. The " red spots," however, could not be found 

 in the blood-platelets, and believing them to be centrosomes, the authors 

 suggested in their paper in the ' Lancet ' that if they could be demonstrated 

 in the blood- platelets, it would settle the nature of these bodies, and close an 

 old existing controversy. 



About two months ago I was fortunate enough to observe these " red 

 spots " in the blood-platelets, and if the following experiment is repeated 

 the spots can be produced in them in every specimen. 



Prepare a neutral solution which contains 3 per cent, sodium citrate, 

 1 per cent, sodium chloride, and 1 per cent, morphine hydrochloride. 

 Draw up into a capillary tube a volume of this solution, and add to it an 

 equal volume of blood drawn freshly from the finger. After allowing the 

 two fluids to mix, incubate the tube at 37° C. for five hours. A film of agar- 

 jelly must now be prepared, which contains a sufficiency of Unna's stain to 

 stain deeply the granules of polymorphonuclear leucocytes when they are 

 spread upon it. One suitable formula for preparing this jelly is given in 

 the 'Lancet' for January 16 and February 6, 1909, and another suitable 

 formula will be found in the first equation in a paper recently published in 

 the ' Proceedings of the Boyal Society,' B, vol. 81, 1909, p. 102. Place a 

 drop of the incubated blood and morphine solution on to a cover glass, which 

 should be inverted and allowed to fall flat on to the agar film. In about 



