First and only edition of a "short but weighty treatise" (Meyer) on protozoa and spermatozoa by the German natural historian Martinus Frobenius Ledermüller (1719-1769). He wrote the essay as a defence of his earlier publication Physicalische Beobachten derer Saamenthiergens (1756). "Ledermüller's brief as well as his comprehensive treatises were accompanied by numerous good illustrations both of spermatozoa and of the microscopes he used, of which he was a connoisseur" (Meyer). Included at the end is a short description of Leeuwenhoek microscopes.
With the library stamp of Oscar Gebhardt, Nürnberg. Some thumbing to title-page and a few occasional spots and minor smudges, otherwise in good condition. Cole 1694; Dobell, p. 412; A.M. Meyer, The rise of embryology, pp. 151-152; Nissen, ZBI 2412.