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II. — On Pigment-Flakes , Pigmentary Particles , and Pigment- 
Scales. By Joseph G. Richardson, M.D., Microscopist to 
the Pennsylvania Hospital. 
The present paper is designed to direct attention to what I con- 
ceive to be an egregious error, by which several microscopists of 
acknowledged ability have been ensnared, — namely, a belief in 
the importance of the “ pigment-cells ” or “ scales ” described by 
Frerichs, of Berlin, as occurring in blood ;* * * § of similar bodies found 
by Drs. Meigs and Pepper, of this city, under like circumstances ; f 
and of the “ pigmentary particles ” or “ celloids ” figured by 
Dr. William Roberts, of Manchester, England ; I most, perhaps 
all of which I assert to be simply and solely accumulations of dirt 
(especially the remains of red blood-corpuscles) in the little excava- 
tions on slides in ordinary use. ' 
Such an accusation as this will, no doubt, at first excite 
astonishment or even ridicule, but of bourse no sane man would 
dare to bring forward a charge of this kind without strong evidence 
in its favour. This evidence I ask each one of my readers to 
furnish me after trying this simple experiment : 
Examine an ordinary jp?afe-glass slide microscopically for dirt- 
pits containing brownish-red matter which may be oxide of iron 
(the remains of the polishing powders used in its manufacture), 
or, if the slide has been long in use, old red corpus: des. If there 
are none already filled up with “ pigment,” rub in faithfully a little 
blood, by which means you can sometimes fill the shallow cavities 
with the debris of the red disks, and so imitate quickly the effect 
probably often produced in a gradual manner by frequently wiping 
small quantities of blood over the glass. Lastly, clean off the slide 
perfectly bright (so as to be sure you leave nothing but artificial 
cells upon it), and examine with a power of 250 diameters. 
The bodies you probably find are accurately described by 
Dr. Roberts as follows : § “ Pigmentary particles ; these objects 
deserve a passing notice from the fact that they are frequent, almost 
constant, if not absolutely constant, objects in urinary deposits, and 
have not hitherto been described. . . They never exist in such 
quantity as to form the entire {sic) of a visible urinary sediment ; 
they are only to be recognized by the microscope. They appear 
especially under two conditions — namely, as free amorphous par- 
* ‘ Clinical Treatise on Diseases of the Liver.’ Sydenham Soc. Translation, 
London, 1860, vol i., p. 320. 
f ‘ Pennsylvania Hospital Reports,’ Phila., 1868, p. 108. 
% ‘Urinary and Renal Diseases,’ second American edition, Phila., 1872, p. 125, 
§ Op. cit., p. 124 et seq. 
