Since all forms of Energy have two modes, potential (or latent) and kinetic (or active), on the plane of physics, this must be true, of course, of Vital Energy.

Life-energy must be present in all living bodies in the forms, respectively, of latent Vital Energy and functioning Vital Energy—energy conserved and available for functioning, and energy expending itself in the living processes of mentality and action.

An individual is able to move his limbs by power of the potential motion stored, or latent, in the muscle-cells of his limbs. Just as a locomotive-engine is enabled to travel by power of the potential motion stored in the steam generated in its boiler. And as in the living organism, so in the engine, the mechanism and the processes that engender in it the potential motion of steam are wholly distinct from those which convert this potential motion into actual motion.

One is able to think, by power of the potential mentality stored, or latent, in his brain-cells. For not only the vital processes which sustain the life of the organism, as those too which enable it to function in terms of living personality and action, but brain-power also must exist in the dual forms, respectively, of potential Faculty and functioning Faculty. So too, Reproductive power. In all of these appear again the modes of Dominance and Recessiveness, of powers positive and manifesting, and of powers negative and latent. And since the female sex is characterised by traits of repose and conservation, and the male sex by traits of action, the dual modes of vital, muscular, cerebral and reproductive energy in potential, and of vital, muscular, cerebral and reproductive energy in course of generating function, range themselves inevitably on the two sides of the living equation as Sex-characteristics differentiating the male organisation from that of the female. Thus ranged, they characterise the two sides of the body as representing, respectively, a right, male side which is the central agency in function, and a left, female side, which is the reservoir of the potential of function.

If then the female mode of functioning is the Potential, or Recessive, a mode of latency, it is to be inferred that the male traits every female creature inherits from her father will, when incorporated in a body of female prepotence, pass into the potential, or Recessive, mode; and will thus become inhibited from developing as male-characteristics. Nevertheless, this male potential will be preserved in that reproductive gland which represents the paternal inherences in her, and will be transmitted, as her contribution to male offspring, in the sex-cells generated by this gland.

While the female inherences every male derives from his mother will, in the presence of the Dominant male-characteristics he derives from his father, retain their latent, or Recessive, mode; and will thus not emerge as female characteristics. The female inherences will be preserved, however, in that reproductive gland which represents the maternal inherences in him; and will be transmitted as his contribution to female offspring.

It will be seen thus that, as in hybrid plants, so in hybrid creatures of both sexes, cells of two sexes are generated: in the male, cells Dominant for maleness and cells Recessive for maleness—female that is; in the female, Recessive cells, prepotent for femaleness, and Dominant, or male, cells.

And of these, the Dominant male sex-cells contributed by the male parent, mating with the Dominant, or male, sex-cells contributed by the female parent, male offspring results. While the Recessive female sex-cells contributed by the female parent, mating with the Recessive, or female, sex-cells contributed by the male parent, female offspring results.

Furthermore, Dominance being paramount in development, it must be from the Dominant inherence imparted by residence in a male organisation to the potential, or Recessive, female Germ-Plasm that the latter derives the new developmental impulse it transmits to sex-cells. While Recessiveness being Life and Faculty in the potential mode, it must be from the Recessive inherence engendered in the Dominant male Germ-Plasm, by residence in a female organisation, that its Dominance, passing into latency, derives a new potential of further evolutionary impetus.