266 



NATURE 



[July 20, 1882 



Mr. Pusey's treatment of the evidence from rudimentary 

 organs does not seem to us more fortunate. His only 

 criticism here is that because organs are rudimentary we 

 have on this account no warrant for concluding that they 

 are useless ; " if these aborted structures were the only 

 ones in which we could see no use, then the explanation 

 would have some locus standi." But here the important 

 fact is lost sight of that all rudimentary organs are the 

 homologues of organs which when of larger size present 

 observable utility. Can it be reasonably supposed that 

 in the case of all the thousands of these "aborted struc- 

 tures," some new function, always unobservable, is per- 

 formed by an organ which by some strange chance happens 

 to be the homologue of an organ which when of larger 

 size performs some other and observable function ? 



Again, the argument from embryology obtains but very 

 scant justice ; only three pages are devoted to it, and the 

 core of the subject is not touched. For the force of this 

 argument does not consist in our seeing " a vast number 

 of animal forms, many of which are very like each other, 

 and their distinctions less pronounced in youth," or in 

 such cases as that of the stripes on the young lion, &c. 

 The force of the argument consists in the progressive 

 imitation of lower morphological types by the successive 

 embryonic stages of higher ones ; and of this very 

 remarkable fact Mr. Pusey takes no notice. 



The argument from palaeontology is dismissed in a 

 similarly high-handed fashion, but somewhat more con- 

 sideration is given to the argument from geographical 

 distribution. The view advanced is " that the facts of 

 distribution can, to a great extent, be shown to have 

 originated in an opposite manner, not by the origination 

 of new forms, but by the destruction of old ones." If 

 this could be shown, no doubt the proof would be one of 

 much importance to science, and would serve largely to 

 modify the argument from distribution ; but the fact 

 certainly has not been proved, or even shown to be gene- 

 rally probable, by the book before us. 



Concerning the specially Darwinian theory of evolution 

 Mr. Pusey says that personally he thinks " whatever else 

 is the origin of species, natural selection certainly is not.'' 

 His reasons for this opinion are that a priori the way in 

 which we should expect natural selection to act " would 

 be by conferring fertility, hardiness, and early maturity " 

 (none of which qualities are presented by the higher 

 Primates) ; and also that allied animals living on the 

 same areas and apparently exposed to similar conditions 

 of life, are nevertheless "dissimilar in a number of minor 

 points, apparently unconnected and without teleological 

 purpose." Now concerning the first of these objections, it 

 seems enough to observe that a priori considerations of this 

 kind are extremely hazardous. Fertility, hardiness, and 

 early maturity may all be good for species, and yet other 

 qualities (perhaps incompatible with them) may be even 

 better, such as high nervous organisation, intelli ence, 

 &c. In short, where the conditions of the problem in 

 any given case are so many and complex, it would be idle 

 to determine beforehand what qualities we should expect 

 natural selection to lay a premium upon — as much so, for 

 instance, as to say, after the event, that a man would be 

 better suited in his environment if he had had a very 

 much more brutal constitution, could run about like a 

 chicken when- a few hours old, and was the most prolific 



animal in creation. And of course the other difficulty, 

 being of a similarly a priori kind* admits of being simi- 

 larly met. There may be a thousand unobservable 

 reasons why, after a long course of evolution, allied 

 species living on the same areas should be dissimilar in 

 minor points of structure, colour, &c. 



We have now briefly noticed all the leading points in 

 Mr. Pusey's criticism, and if we had more space we might 

 go more in detail with him. But we have said enough to 

 show that we deem his strictures throughout to err on the 

 side of over-scepticism. In science, as in everyday life, 

 true judgment is shown, not by suspending our decision 

 until a theory is demonstrated by observation, but by 

 yielding assent to probability in a degree commensurate 

 with the evidence. At the same time, it is, of course, 

 most important that a clear distinction should always be 

 drawn between a probability, however high, and a proved 

 fact. In every department of inquiry, therefore, the 

 hyper-critical mind is of service in insisting upon this 

 distinction when there is danger of its being neglected; 

 and in view of this consideration we think there are many 

 evolutionists who would do well to read Mr. Pusey's 

 work. As we have already said, we do not consider that 

 this work has in any way affected the main evidences of 

 evolution ; but it is well calculated to steady the course 

 of speculative thought in a direction where with less 

 hurry there may be more speed. 



George T. Romanes 



CR YSTALLOGRAPHY 



Geometrische Krystallographie. Von Dr. Th. Liebisch 



(Leipzig : Wm. Engelmann, 18S1.) 



THIS is the most complete and exhaustive book on 

 crystallography which has been so far published, 

 and it is especially characterised by the importance 

 assigned to the dualism observed in crystallographic 

 problems considered as relations of a system of planes or 

 lines connected together by the law of rational indices. 

 The book consists of three main parts — the first dealing 

 with the general relations of a system of planes and lines 

 subject to the law of rational indices ; the second with 

 crystallographic representation and construction ; and 

 the third with the developments of the six crystallographic 

 systems and the determination of crystals. 



The general problems in the first part are treated by 

 the processes of modern geometry. The problem of the 

 transformation of the axial system is very exhaustively 

 treated, but curiously enough Dr. Liebisch seems unac- 

 quainted with the elegant solution of this problem, given 

 by the late Prof. Miller in his Tract on Crystallography 

 (1863). The analysis of this problem, given by Dr. 

 Liebisch, is laborious and somewhat complicated, and 

 the results are not really more general than those of Prof. 

 Miller. Dr. Liebisch has entered into the question of 

 the conditions of perpendicularity in a crystal system, but 

 his analysis is not so elegant as that of Prof. H. J. S. 

 Smith, nor is it capable of more ready application than 

 the latter. The chapter treating of this portion of the 

 subject is largely occupied by the proofs of the ordinary 

 propositions of spherical trigonometry by means of a 

 cumbrous notation and an analysis of great difficulty. 

 One can hardly believe that this analysis is needed by 



