The chromatoid body in the spermatogenesis of the grass-snake, Natrix natrix, has been studied by the use of phase-contrast microscopy, vital dyes, and histochemical tests.
It first appears during the growth of the primary spermatocyte and is also seen in the secondary spermatocyte and late spermatid, but is absent at metaphases of both the maturation divisions, in the early spermatid, and during the final stages of spermateleosis. It does not make any visible contribution to the final make-up of the spermatozoon.
In living cells it gives a very low phase change, and is not stained by neutral red or Janus green. The histochemical study reveals that it consists mainly of RNA and of proteins with abundant acidic and basic groups.
It is tentatively suggested that its function is to provide basic proteins for the final maturation of the chromatin in the nucleus of late spermatid.