NATURE 



[July 7, 19 10 



toxins. Twenty years ago I ventured with bated 

 breath to hint the possibility of its education. The 

 result is that the microbe and not the sword is the 

 ultimate "empire-builder"; and subject-races will 

 either absorb or expel their conquerers. The argu- 

 ment is extended to alcohol and narcotics. All races who 

 win their freedom from vicious indulgence must first 

 be slaves to it. Insusceptibility to its charm, though 

 not precisely parallel to disease-immunity, is, like it, a 

 product of germinal variation. Meanwhile, selection 

 slowlv eliminates those who do not possess it. If it is 

 true that the English are the most drunken of existing 

 races, and that "about one death in seven" amongst 

 them is due to alcohol, it has its work cut out for it. 

 Still, it is at work; and any attempt to interfere with 

 it by the total suppression of alcohol would simply 

 result in the production of a more susceptible race. 



Fortunately, though susceptibility is germinal, in- 

 dulgence is an acquired habit. It follows that the 

 children of drunkards will not necessarily follow in 

 their parents' steps, and Karl Pearson confirms this 

 from biometric data. The same reasoning applies to 

 slum-dwellers. Here also the injury is somatic and 

 not germinal, and would disappear if the conditions 

 were improved ; it is not transmitted, but reproduced 

 in the offspring, which the experience of Dr. 

 Barnardo's Homes shows is still capable of healthy 

 development. Slums are continually recruited from 

 outside; it is probable, therefore, that little, if any, 

 germinal mischief has been produced. But it can be 

 shown on Dr. Archdall Reid's own principles that, 

 given time, an adapted and degenerate race would 

 develop, which would be parasitic on the communily. 

 and probably prolific. 



The chapters on mind I must leave to the psych- 

 ologist. Lankester is followed in seeing in ' the rela- 

 tively enormous size of the brain in man and the 

 corresponding increase in its activity and capacity," 

 the fundamental distinction between man and other 

 animals. " Educability is nothing more than a power of 

 growing mentally under the stimulus of experience." 

 This is inherited, while the resulting mental acquire- 

 ments are not. The real test of education is the 

 quality of thinking produced. I cannot, however, 

 follow the author in his condemnation of Karl Pear- 

 son's Huxley lecture, the conclusions of which I 

 believe to be, not merely perfectly sound, but of the 

 deepest importance. Dr. Archdall Reid tells us that 

 "ability is inborn"; Karl Pearson says it is "bred." 

 I fail to see the distinction. Feeble-mindedness is 

 found to consist in "incapacity to learn " and to be a 

 "reversion to a pre-human mental state." Being ger- 

 minal, it is inherited, and the community is justified 

 in restraining its marked fertility. 



Here I must conclude my review of a very remark- 

 able book ; the more remarkable as it is the work of 

 a man somewhat aloof from the scientific world, and 

 written as the recreation of a strenuous professional 

 life. The author invites criticism, and I have not 

 stinted it. He will doubtless get plenty more. 



Perhaps Dr. Archdall Reid's more vulnerable point 



is the superior certitude which he (and Dr. Donkin) 



claim for deduction over observation and experiment 



(which is onlv observation of facts not immediately 



NO. 2123, VOL. 84] 



patent!. It is true that when we come across an 

 apparenth- irreconcilable fact, its improbability depends 

 on the certitude of the law with which it conflicts. It 

 mav be due to experimental error in its widest sense; 

 but it may be the germ of a new discovery. Newton 

 laid aside his theory for a time because he could not 

 reconcile it with the moon's motion. But Greenwich 

 did not abandon it when it was found that the path 

 of Halley's comet was not an ellipse. Certitude is 

 built up by accumulated verification. Even mathe- 

 matics, which are purely deductive, cannot wholly dis- 

 pense with it. It was long thought that the conver- 

 sion of linear into circular motion was impossible until 

 Peaucellier effected it. And even so distinguished a 

 mathematician as Sylvester once told me that he had 

 published a number of theorems which, when tested 

 arithmetically, proved to be untrue. Experiment 

 cannot always wait on dedwetion. Rontgen's great 

 discovery was an accident. ■ A discrepancy in the 

 weight of nitrogen revealed argon. It would possibly 

 have been a long time before physicists found out for 

 themselves Brownian motion and osmotic pressure 

 unless botanists had done it for them. Darwin found 

 by experiment that cross-fertilisation was advan- 

 tageous to plants, and it is difficult to see how the fact 

 could have been arrived at in any other way. 



Huxley must have projected a prophetic eye into 

 the future when he wrote : — 



"The great danger which besets all men of large 

 speculative faculty, is the temptation to deal with the 

 accepted facts in natural science, as if they were not 

 only correct but exhaustive ; as if they might be dealt 

 with deductively, in the same wav as propositions in 

 Euclid mav be dealt with. In reality every such state- 

 ment, however true it may be, is true only relatively 

 to the means of observation and the point of view of 

 those who have examined it. So far it may be de- 

 pended upon. But whether it will bear every specu- 

 lative conclusion that may be logically deduced from 

 it, is quite another question." 



The warning is not unneeded in many directions. 

 It is, I think, particularly needed in regard to Dr. 

 Archdall Reid's impatience with biometry and 

 taxonomy, or rather, I should say, imperfect acquaint- 

 ance with their aim and methods. He appears to 

 jthmk that biometric method begins and ends with 

 mere enumeration. But such a research as that of 

 Karl Pearson on the distribution of stars in space 

 would show him that it goes a good deal farther. 

 As Karl Pearson tells us, biology "has now developed 

 theories of such complexity, that without the aid of 

 the highest mathematical analysis it is wholly unable 

 to state whether its theories are accurate or not." For 

 my part, when a distinguished mathematician is will- 

 ing to devote his splendid gifts to the task, my atti- 

 tude is not querulous, but one of profound gratitude. 



And taxonomy is even less a ground for impatience. 

 For, as Linnseus saw, its real aim Is to embrace all 

 organisms in a natural classification. The principle ot 

 descent is implicit in this, and it was therefore 

 towards it that all taxonomists were unconsciously 

 working. Far from being hostile, it was amongst 

 the systematists— Hooker, Asa Gray, Bentham, Bates, 

 and Wallace— that Darwin found his most ardent 

 champions. W- T. Thiselion-Dyek. 



