HEREDITY AND EVOLUTION 103 



structure and function. Such is the coherence and 

 solidarity of species, as illustrated in separation of 

 germ-cells for reproduction, that the acquisitions by 

 the individual prove gain for the species. If there be, 

 beyond this, as most of us are now convinced there 

 is, evidence for origin of species by natural selection, 

 we are only finding that the first intention expands 

 into enlarged intention, making provision for a general 

 organic advance. Whether we are to interpret this 

 movement according to a quicker rate of progress, 

 such as Darwin has suggested, or according to a 

 slower rate, such as Weismann propounds as the 

 correct time-measurement, the general law of advance 

 stands out as a leading feature in Nature. Nature s 

 movement is one of evolution. And even if the 

 slower time-measurement be thought the more 

 accurate, there is striking testimony showing that 

 deterioration has many checks placed upon it, while 

 progression has not only many safeguards, but many 

 active supports. The general law thus remains 

 clear, however many the checks encountered in its 

 application ; hence the aid we find for interpretation 

 of Nature s methods in the law of natural selection. 

 Apparent hindrances are brought into line for service 

 under the first supreme law of advance. The struggle 

 for existence, with all its records of superabundant 

 production of life, and of subsequent destruction of 

 life, works for development of species as a whole. 

 When at length heredity is included in its full 

 significance, accepting Spencer s assumption that the 

 units of which any organism is built up have an 

 innate tendency to arrange themselves into the shape 

 of that organism, the young life is seen to receive and 



