76 CHAPTERS ON EVOLUTION. 



besets the real differences between one speck of protoplasm and 

 another and apparently similar speck. 



But our want of knowledge of such points may not leave untouched 

 the primary question concerning the nature of life, to which all the pro- 

 perties and qualities of protoplasm, all the varied forms and faces of 

 living beings, are due. On the contrary, it is possible by analogy to 

 arrive at some broad views concerning the nature of life at large, 

 and to such considerations we may now shortly attend. Physiology 

 points out to us that the properties of protoplasm and all its powers 

 of being and becoming are resident within its own substance, and are 

 dependent upon the energy of which it is the seat. Supply appropriate 

 conditions, and the forces of the protoplasm will convert the primitive 

 germ into the form of its progenitor. There is a transformation of 

 force and matter of one kind, into force and matter of another kind 

 therein involved. Such facts point to material powers and forces 

 resident in, and peculiar to, protoplasm as the prime movers of the 

 changes and developments that substance undergoes. As clearly, 

 too, does the transmission of parental likeness from generation to 

 generation argue for the existence of some material and physical 

 basis for the carriage, by the protoplasm-germ, of the features of the 

 species. If so much be admitted, it seems illogical to deny that 

 whatever properties the protoplasm of germ or adult exhibits depend, 

 strictly speaking, upon the chemical and physical properties of that 

 substance. Thus we approach the idea that this mysterious " life;" 

 which no one has yet successfully defined for the plain reason that 

 the terms of the definition are unknown simply represents the sum- 

 total of the energies of the physical, chemical, and other properties of 

 protoplasm. Nowhere do we find life dissociated from protoplasm; 

 and this fact alone argues in favour of the view that the " vital force " 

 of the scientist or the "vital spark" of the poet, is in each case merely 

 the convenient and summary expression of that high form of energy, 

 which corresponds to no one force in nature, but to all combined. 



If this hypothesis be deemed essentially materialistic as un- 

 questionably it will be from certain points of view its supporters 

 still possess a distinct coign of vantage in a simple and logical 

 appeal to the facts and phenomena of nature and life as they stand. 

 In addition to the pregnant fact just mentioned, namely, that life 

 requires for its exhibition a material basis seen in protoplasm, the mere 

 considerations that this substance is composed of no unknown 

 elements, but of well-defined and common substances, and that its 

 composition is not ethereal but material, support the view that life is 

 no mysterious aura, but a collocation of the forces and energies and 

 of the material substances which make protoplasm. Life is a property 

 of protoplasm such is the latest product of scientific thought and 

 research. The forces which make protoplasm are regarded as those 



