342 NATURALLY SCIENCE. May, 
lightened the rest of the skull by over 5 per cent. in the fifty speci- 
mens (mainly Italian) which I weighed. Whatever estimate may be 
formed of the remaining portion of the reduction in the European jaw, 
we still have to deduct the effect of disuse during lifetime and the 
direct or transferred effect of sexual and social selection in repressing 
prognathism. What grounds can we have for assuming that any 
residue remains which can justly be claimed as a proof of the 
inheritance of the effects of ancestral disuse ? § 
In endeavouring to establish the inadequacy of Natural Selection, 
Mr. Spencer puts forth contentions or assertions which manifestly 
overpass the bounds of accurate and logical reasoning. He holds, for 
instance, that if Natural Selection does not cause ‘a frequent survi- 
val” of individuals possessing any particular trait, it can ‘neither 
cause nor aid” any change in that direction. But surely it is as 
rigidly inevitable as any arithmetical or mathematical fact that the 
occasional elimination of an unfavourable characteristic must propor- 
tionally affect the general average. Nay, the elimination of a single 
individual thus characterised has, ifso facto, altered the average among 
the survivors. There is not the least reason, therefore, for accepting 
the strangely unphilosophical dictum that an evolutional cause or 
factor will not act at all unless it acts in considerable or important 
degrees. We may safely allow science and reason to implant in us a 
perfectly firm and unwavering conviction that every cause, however 
weak, will produce its proportional effect; and we may expect that 
the long-continued and cumulative effect of even infinitesimal forces 
or tendencies may become perceptible in the course of sufficient time. 
“Mr. Spencer has unintentionally exaggerated the extent of the diminution. A 
comparison of his statements (Principles of Biology, § 166, footnote) with the skulls 
which he inspected at the College of Surgeons will prove to any careful measurer 
that the jaw, which was too hastily assumed to be ‘‘ an average English jaw,’’ must 
actually have been the smallest English jaw in the collection—that, namely of a 
female skeleton (No. 70a) with exceptionally delicate features. Founded on such a 
basis, his ideas and statements concerning the ‘‘ dwindling away " of the jaw go far 
beyond the sober facts. As Mr. Spencer's disciples thus learn to overrate the decrease 
of the jaw, so also they become apt to underrate the reducing causes. Thus Mr. F. H. 
Collins (compiler of ‘‘ An Epitome of the Synthetic Philosophy,” an abstract of Mr. 
Spencer’s works and teachings, published with an approving preface from the hand of 
the master himself) represents the amount of nutriment required by the whole jaw 
as a grain a day and calls this ‘‘a large estimate’ (The Diminution of the Faw in the 
Civilised Races an Effect of Disuse, p. 12). A little arithmetic will show that the pro- 
portional share of daily nutriment for the jaws with their muscles, &c., is some sixty 
times greater than this, without including liquid. Master and pupil alike seriously 
underrate the extent of variation, and ignore the facts that the reduction in the 
jaw is largely correlated with a similar reduction in the skull as a whole, and that 
the reduction of weight to be moved would allow a proportional economy in the 
bones and muscles and limbs and body that carry the lightened head with its 
lightened jaw; and all this allows still further and complicatedly cumulative economy 
in the alimentary, circulatory, respiratory,and food-procuring organs, which only 
have to provide a lessened amount of duly prepared nutriment for the economised 
parts. Arithmetically estimated, the case for economy is made to appear hundreds 
of times weaker than a fair consideration of the relevant facts would justify. 
