392 THE POPULAR SCIENCE MONTHLY. 



back to the genesis worked out by Mr. Herbert Spencer in the part of 

 his " Principles of Psychology " entitled " Physical Synthesis." 



For let us for a moment try to imagine a nervous system being 

 produced, or increased in value, by natural selection of spontaneous 

 variations alone, without the aid of functional variations at all. It is 

 easy to see that an animal or a plant may vary indefinitely here or 

 there in color, or in hardness of skin, or in woodiness of tissues, and 

 so forth ; and it is easy to see that among these truly " accidental " 

 variations * some may be better adapted to their particular environ- 

 ment than others. But can we imagine, say, an eye to be produced by 

 a series of such individual accidents ? I do not say a human eye, but 

 a simple pigment cell, with a nerve given off from it to a ganglion as 

 in the case of the Amphioxus f And if we can imagine this (which I 

 can not), can we imagine a child being born into the world, gifted, I 

 do not say with innumerable faculties never possessed by his ancestors, 

 but with a single nerve-cell or nerve-fiber more than they possessed ? 

 Just let us look at what a palpable absurdity this notion implies. 



Here is William Jones's head, containing an average human brain, 

 developed on the same pattern as his father's brain (or as his father's 

 in part and his mother's in part) : and here in a particular spot in a 

 particular convolution of it, by a combination of mere physical cir- 

 cumstances, has arisen a totally new and hitherto non-existent nerve- 

 cell. Clearly, this is an acquisition to the race, by way of spontaneous 

 variation. But what is the functional use of this new nerve-cell? 

 What physical circumstance decides whether it is to answer to a new 

 movement in the left little finger, or to a single creative element in the 

 composition of a future fugue ? Let us grant a little more : let us 

 suppose the surrounding cells are all concerned in the appreciation of 

 color, or in the manipulation of numbers. Will the new cell in the 

 first case answer to a new and hitherto undiscovered color or to a fur- 

 ther aesthetic pleasure in an existent color, or to a higher synthesis into 

 which colors enter as elements ; or what in the second case will be its 

 mathematical value ? Again, what good will it be without a whole 

 network of connecting fibers which will link it to percipient structures 

 in the eye on the one hand, and to all the various higher layers in the 

 stratified hierarchy of color-thought elements or number-dealing ele- 

 ments on the other hand ? Granted that one man in a hundred was 

 born with one such new cell in his brain, and (setting aside the ques- 

 tion how the cell comes to have any function at all) what are the 



* It is a great pity that to this day one is always obliged to employ this useful terra 

 with a caution in the way of quotation-marks, in order to avoid a supposed philosophical 

 scholar's-matc from sixth-form critics. " Accidental " in biology means, of course, " pro- 

 duced by causes lying outside the previous vital history of the race " ; in a word, " indi- 

 vidual." Among such accidental variations survival of the fittest preserves a few. But 

 it is annoying that one can never use so transparent a phrase without being informed 

 magisterially by a lofty reviewer that the word accidental is unphilosophical, and that 

 nothing ever happens in nature without a cause. 



