May 31, 1895.] 



SCIENCE. 



599 



now ones by means of growth, plus their 

 chemical and formal transformation as an 

 architecturally self-adjusted aggregate, by 

 means of metabolism, is all that is re([uired 

 in an hypothesis of inheritance. The other 

 properties of living matter, such as its via- 

 cosity, free and interfacial surface-tension, 

 osmotic properties, its limit of saturation 

 ■with water, its segmentation into cells, in 

 short, its organization, must be the result 

 of the operation of forces liberated bj- its 

 own substance during its growi:h by means 

 of metabolism. We cannot exclude exter- 

 nal forces and influences, such as chemism, 

 light, heat, electricity, gravity, adhesion, 

 exosmosis, food, water, air. motion, etc., in 

 the operation of such a complex mechanism. 

 It is these agencies that are the operators 

 of the living mechanism, which in its turn 

 makes certain successive responses in a way 

 that is determined within limits by its own 

 antecedent physical structure and conse- 

 quent dynamical properties. The parts of 

 the whole apparatus are kept in a condition 

 of continuous ' moving equilibrium ' by ex- 

 ternal agencies, to borrow a phrase of Mr. 

 Spencer's. 



This view, it will be seen, leads to a de- 

 terminism as absolute as that of the Neo- 

 Darwinists, but upon a wholly different 

 basis. It leads to the denial of the direct 

 mutability of the germ by any means other 

 than the transformation, chemical and 

 structural, through metabolism of the 

 germinal mechanism. It not onlj' compels 

 us to deny that the germ can be at once so 

 eflected by external blows as to transmit 

 changes thus produced hereditarily except 

 under exceptional conditions, as we shall 

 see later. It denies also, by implication, that 

 the cj'toplasm can be so modified, except 

 indirectly, or through architectural transfor- 

 mations of its ultramicroscopic structure. 



It is also compelled to deny that spon- 

 taneous or autogenous characters can either 

 arise or be transmitted without involving 



the principle of the conservation or correla- 

 tion of force, since no transformation of 

 such a mechanism can take place without 

 involving forces directly or indirectly ex- 

 erted by the external world. In short, the 

 energj^ displayed by a living molecular sys- 

 tem from within must be affected bj^ ener- 

 gies coming upon it from without. All 

 characters whatsoever were so acquired, so 

 that the truth is that there are no others to 

 be considered. Characters acquired tln-ough 

 the interaction of inner and outer forces are 

 the only ones possible of acquirement. 



That througli reciprocal integi-ation (fer- 

 tilization and formation of an oosperm) this 

 rule may have apparent exceptions, through 

 the compounding of two molecular mechan- 

 isms of different strengths, dynamically 

 considered, it is impossible to deny in the 

 face of the evidence of breeders. Such ex- 

 ceptions are apparent, however, and not 

 real, as must follow from dynamical theory. 



The sorting process, called natural selec- 

 tion, is itself dj-namic, and simply expresses 

 the fact that, by an actual operation with a 

 living body of a certain kind, something 

 more than a balancing of forces is involved 

 between internal and external energies 

 whenever a survival occurs. The princi- 

 ples of dynamics therefore apply in all 

 strictness to natural selection. 



What it is that makes crosses or hj'brids 

 more variable and often more vigorous 

 than inbred forms must also have a dynamic 

 explanation, since there can be no increased 

 activity of metabolic processes without an 

 increased expenditure of energj' and an in- 

 creased rate of molecular transformation. 



Variations cannot be spontaneous, as 

 Darwin himself was aware. The only way 

 in which they can be supposed to have 

 arisen is bj- the blending of molecular dy- 

 namical systems of differing initial potential 

 strengths, by the conjugation of sex-cells 

 (reciprocal integration), and by means of 

 variations in the interactions of such result- 



