cules, each of which is composed of atoms of five elements carbon, 

 oxygen, nitrogen, hydrogen, and sulphur, differing not one iota from 

 the molecules of inorganic bodies, except that it acquires the special 

 power of reproduction, by virtue of the peculiar combination of its 

 atoms, which power is wanting in the inorganic world, whose molecules 

 are composed of similar atoms, but in different combinations. This is 

 the only difference between the organic, or life, world, and the inorganic, 

 or lifeless, world life being, as compared with unlife, but the power of 

 reproduction. As examples of this, we may take crystals, the most 

 perfect development of inorganic nature, and the moneron, the least 

 perfect development of organic nature; and the difference between 

 them is almost //, certainly less than between the parents and offspring 

 in many life-forms. The crystal molecules are composed of elementary 

 chemical atoms, as are the moneron molecules ; but the former grow 

 by particles being deposited on particles externally, while the latter 

 grow by particles penetrating from without, or being absorbed into 

 the interior and becoming assimilated by the plasm, fresh molecules 

 being evolved in the process, this special power of reproduction being 

 generated by the peculiar combination of the atoms. This argument 

 appears to me to be logically and scientifically sound, and disposes 

 altogether of the notion of a break of continuity between the living 

 and the unliving worlds, which is such a formidable difficulty to many 

 minds. The plasm thus formed by the aggregation of life molecules 

 gradually differentiates into protoplasm and nucleus, which together 

 form a simple cell ; and this cell partakes, by heredity, of the nature 

 and properties of its parent form, and also, by adaptation to different 

 circumstances surrounding its existence, acquires fresh properties, which, 

 together with the inherited properties, it transmits to its progeny, thus 

 evolving a still more complex form, inheriting the acquired and 

 inherited properties of its parent, and again acquiring fresh properties ; 

 and so on, ad infinitum, through the various life-forms we know have 

 been developed in the pedigree of man and animals, through Amoebae, 

 Synamoebae, etc., as in the genealogy given above. 



In the course of the development of different life-forms heredity 

 which, in plain English, is unconscious memory generated in the first 

 life-form and transmitted through all the different species is the sole 

 factor in the preservation of the parent properties ; while adaptation 

 to surrounding conditions and circumstances, natural selection in the 

 struggle for existence, and sexual selection in the struggle of the 



