394 THE POPULAR SCIENCE MONTHLY. 



itself be a dried-up form of a still earlier peach ; and this will be 

 equally true even if all the existing peaches can be shown to be de- 

 scended from nut-like almonds. For the almond is a plum by family ; 

 and all the other plums have juicy fruits ; while one of them, the apri- 

 cot, closely approaches the almond-peach group in most of its char- 

 acters. Seeing, then, that the almond must almost certainly be de- 

 scended from juicy fruit-bearing ancestors, nothing is more natural 

 than that under altered circumstances it should revert, per saltum, to a 

 juicy peach. But to suppose that the peach type was originally de- 

 veloped per saltum from an almond is to suppose that it varied at once 

 in several separate ways, all equally and correlatively adapted to a 

 particular mode of dispersion. It is to suppose that accident could do 

 in a minute what we have every reason to believe can only be done 

 by infinitesimal variations and infinite selection. 



But if the naturalist can not imagine the production of a peach de 

 novo out of an almond at a single jump, how can he imagine the pro- 

 duction of a new thinking element in a human brain ? How can he 

 suppose that the accidental introduction of one more little bit of mat- 

 ter into that vast organized labyrinth — a mighty maze, but not without 

 a very definite and regular plan — can have any kind of intelligible 

 relation to the complicated system of cross-connections and superim- 

 posed directive departments which make it up ? And if it be objected 

 that the view taken above of the constitution of the brain is wooden 

 and mechanical, I would answer that it is certainly absurdly diagram- 

 matic and inadequate, but that it is so far right in that it insists upon 

 making believers in spontaneous variation try to realize their own un- 

 thinkable attitude. As to materialism, surely it is more profoundly 

 materialistic to suppose that mere physical causes, operating on the 

 germ, can determine minute physical and material changes in the 

 brain, which will in turn make the individuality what it is to be, than 

 to suppose that all brains are what they are in virtue of antecedent 

 function. The one creed makes the man depend mainly upon the 

 accidents of molecular physics in a colliding germ-cell and sperm- 

 cell ; the other creed makes him depend mainly upon the doings and 

 gains of his ancestors, as modified and altered by himself. 



And now let us look at this second creed, in order to see how far 

 it surpasses its rival in comprehensibility, concinnity, and power of 

 explaining all the phenomena. If it be true that all nerve-increment 

 and especially all brain-increment is functionally produced, we can 

 easily understand why each new cell or fiber should stand in its true 

 and due relation to all the rest. It will have been evolved in the 

 course of doing its own work, and it will be necessarily adapted to it 

 because the act of working has brought it into being. There will be no 

 doubt whether the new cell governs the peculiar action of the left little 

 finger in performing that amusing conjuring trick, or is, on the con- 

 trary, connected with the perception of orange-red, because the cell 



