874 THE INDUCTIONS OF BIOLOGY. 



still left unanswered the question — icJiy does gamogenesia 

 recur ? And to this the reply suggested was, that the ap- 

 proach towards general equilibrium in organisms, "is ac- 

 companied by an approach towards molecular equilibrium in 

 them ; and that the need for this union of sperm-cell and 

 germ-cell, is the need for overthrowing this equilibrium, and 

 re-establishing active molecular change in the detached germ 

 — a result which is probably effected by mixing the slightly- 

 different physiological units of slightly- different individuals.'^ 

 This is the hypothesis which we have now to consider. Let 

 us first look at the evidences which certain inorganic pheno- 

 mena furnish. 



The molecules of any aggregate which have not a balanced 

 arrangement, inevitably tend towards a balanced arrangement. 

 As before mentioned [First Principles, § 103) amorphous 

 wrought iron, when subject to continuous jar, begins to arrange 

 itself into crystals — its atoms assume a condition of polai 

 equilibrium. The particles of unannealed glass, which are so 

 unstably arranged that slight disturbing forces make them 

 separate into small groups, take advantage of that greater 

 freedom of movement given by a raised temperature, to ad- 

 just themselves into a state of relative rest. During any 

 such re-arrangement, the aggregate exercises a coercive force 

 over its units. Just as in a growing crystal, the atoms suc- 

 cessively assimilated from the solution, are made by the al- 

 ready-crystallized atoms to take a certain form, and even to 

 re-complete that form when it is broken ; so in any mass of 

 unstably-arranged atoms that passes into a stable arrangement, 

 each atom conforms to the forces exercised on it by all the 

 other atoms. This is a corollary from the general law of 

 equilibration. We saw {First Principles, § 130) that every 

 change is towards equilibrium; and. that change can never 

 cease until equilibrium is reached. Organisms, above 



^11 other aggregates, conspicuously display this progressive 

 equilibration; because their units are of such kinds, and so 

 conditioned, as to admit of easy re-arrangement. Those 



