584 APPENDIX A. 



Hence the maintenance of tlie individual and the propagation 

 of the race being respectively aggregative and separative, necessarily 

 vary inversely. Every generative product is a deduction from 

 the parental life ; and, as already pointed out, to diminish life is 

 to diminish the ability to preserve life. The portion thrown off 

 is organised matter ; vital force has been expended in the organ- 

 isation of it, and in the assimilation of its component elements ; 

 which vital force, had no such portion been made and thrown off, 

 would have been available for the preservation of the parent. 



Neither of these forces, therefore, can increase, save at the 

 expense of the other. The one draws in and incorporates new 

 material ; the other throws off material previously incorporated. 

 The one adds to ; the other takes from. Using a convenient 

 expression for describing the facts (though one that must not be 

 construed into an hypothesis), we may say that the force which 

 builds up and repairs the individual is an attractive force, whiJst 

 that which throws off germs is a repulsive force. But whatever may 

 turn out to be the true nature of the two processes, it is clear that 

 they are mutually destructive ; or, stating the proposition in its 

 briefest form — Individuation and Reproduction are antagonistic. 



Again, illustrating the abstract by reference to the concrete, 

 let us now trace throughout the organic world the various phases 

 of this antagonism. 



§5. All the lowest animal and vegetable forms — Protozoa and 

 Protophyta — consist essentially of a single cell containing fluid, 

 and having usually a solid nucleus. This is true of the Infu- 

 soria, the simplest Entozoa, and the microscopic Algae and Fungi. 

 The organisms so constituted uniformly multiply by spontaneous 

 fission. The nucleus, originally spherical, becomes elongated, 

 then constricted across its smallest diameter, and ultimately 

 separates, when " its divisions," says Prof. Owen, describing the 

 process in the Infusoria, " seem to repel each other to positions 

 equidistant from each other, and from the pole or end of the 

 body to which they are nearest. The influence of these distinct 

 centres of assimilation is to divert the flow of the plasmatic fluid 

 from a common course through the body of the polygastrian to 

 two special courses about those centres. So much of the primary 

 developmental process is renewed, as leads to the insulation of 

 the sphere of the influence of each assimilative centre from that 

 of the other by the progressive formation of a double party wall 

 of integument, attended by progressive separation of one party 

 wall from the other, and by concomitant constriction of the body 

 of the polygastrian, until the vibratile action of the superficial 

 cilia of each separating moiety severs the narrowed neck of 

 union, and they become two distinct individuals." * Similar in 



* "Parthenogenesis," p. 8. 



