Red blood corpuscles

Corpuscle \Cor"pus*cle\ (-p[u^]s*s'l), n. [L. corpusculum, dim.
   of corpus.]
   1. A minute particle; an atom; a molecule.
      [1913 Webster]

   2. (Anat.) A protoplasmic animal cell; esp., such as float
      free, like blood, lymph, and pus corpuscles; or such as
      are imbedded in an intercellular matrix, like connective
      tissue and cartilage corpuscles. See {Blood}.
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            Virchow showed that the corpuscles of bone are
            homologous with those of connective tissue.
                                                  --Quain's
                                                  Anat.
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   3. (Physics) An electron. [archaic]
      [Webster 1913 Suppl.]

   {Red blood corpuscles} (Physiol.), in man, yellowish,
      biconcave, circular discs varying from 1/3500 to 1/3200 of
      an inch in diameter and about 1/12400 of an inch thick.
      They are composed of a colorless stroma filled in with
      semifluid h[ae]moglobin and other matters. In most mammals
      the red corpuscles are circular, but in the camels, birds,
      reptiles, and the lower vertebrates generally, they are
      oval, and sometimes more or less spherical in form. In
      Amphioxus, and most invertebrates, the blood corpuscles
      are all white or colorless.

   {White blood corpuscles} (Physiol.), rounded, slightly
      flattened, nucleated cells, mainly protoplasmic in
      composition, and possessed of contractile power. In man,
      the average size is about 1/2500 of an inch, and they are
      present in blood in much smaller numbers than the red
      corpuscles.
      [1913 Webster]