i 



Januarv 5, 1S99] 



NA TURE 



219 



The discussion of rudimentary organs from the author's 

 point of view (p. 162 et seq.) is one of the best illustrations 

 of the effect of introducing ultra-scientific "explanations" 

 into the domain of natural science that will be found 

 throughout the book. These organs are not vestigial, 

 but prophetic. Such a rudiment 



"may be where it is — simply because it indicates an 

 original direction of growth, or of development, which 

 was made part of the vertebrate Plan from the beginning 

 of the series, for the very reason of its potential adapt- 

 ability to an immense variety of purposes. Moreover, the 

 arrest of such tendencies of growth, at a given point in 

 the series, may well have been part of the same Plan 

 from the beginning " (pp. 175-176). 



The general public, who have hitherto been accustomed 

 to consider the essence of the theory of evolution to be 

 contained in the statement that man is descended from 

 a tailed ancestor, will no doubt hail this statement of the 

 Duke's with acclamation, because the rudimentary tail 

 (which is discussed on p. 157) may after all be only "an 

 arrested tendency of growth." The other logical alter- 

 native, that it is a preparation for a tail to be developed 

 by generations yet unborn, is quite legitimate from this 

 point of view, but the author will doubtless not insist 

 upon this deduction. .Similarly the rudimentary teeth 

 and pelvic limbs of whales, which are also somewhat 

 fully considered, are not necessarily vestigial in the sense 

 of being the remnants of structures that were at one time 

 functional. These rudiments are likewise to be regarded 

 as "arrested tendencies of growth," or else as predeter- 

 mined preparations for the transformation of whales into 

 land animals. Honestly we prefer the Darwinian e.\- 

 planation — even though we have to face the difficulty of 

 the electric organs of the Torpedo. 



We have discussed these essays in the spirit of contro- 

 versy because they are purely controversial in character. 

 They have been considered also at greater length than 

 their scientific importance warrants. Strictly speaking, 

 it is ditificult to see what class of readers are influenced 

 by writings of this kind ; certainly not working biologists 

 of any school of thought. But the unlimited hospitality 

 extended by the editors of high-class popular magazines 

 to essayists of the calibre of the author of the present 

 work, shows that such writers have the public ear, and it 

 seems desirable to let the public know that the authority 

 which is wielded by these knights of the pen is not con- 

 ferred by those whose special studies in the field of biology 

 might be reasonably supposed to give them the right of 

 conferring such authority. There are some minds that 

 may be satisfied with the word " Plan" as an all-sufficient 

 explanation of natural mysteries yet unsolved. Like " the 

 blessed word Mesopotamia,'" it may convey much com- 

 fort to such minds; but the earnest seeker after scientific 

 truth will not be deluded, and he will still go on groping 

 his way towards a knowledge of the processes by which 

 the universe has been evolved by the only legitimate 

 methods of observation, experiment, induction and 

 deduction. It may be that, as Darwin long ago sug- 

 gested, a definite set of characters undergoing selection 

 may by inheritance tend to go on varying in the same 

 direction, and so give to the course of development an 

 impetus as though from some internal agency. But this 

 agency would be only apparent, and not real in the sense 

 NO. 1523, VOL. 59] 



of being a special entity. It would be a necessary con- 

 sequence of heredity combined with other properties of 

 living organisms which are "internal" in the same sense 

 that crystalline form is due to the play of internal forces, 

 and in no other sense. If, as the recent investigations of 

 Prof Karl Pearson seem to show, there is a tendency on 

 the part of a race to undergo change in a definite direc- 

 tion, this tendency is the necessary consequence of 

 correlation between fertility and other characters of the 

 organism. To say that the laws of inheritance are the 

 expressions of a preconceived Plan may be a statement 

 of pious opinion, but as a scientific explanation it is quite 

 devoid of value. R. Meldol.'V. 



THE TIDES POPULARLY AND PROPERLY 

 TREA TED. 

 The Tides and Kindred P/ienoinena in the Solar System. 

 By Prof G. H. Darwin, Plumian Professor of Astro- 

 nomy, Cambridge. Pp. xviii -I- 342. (London : John 

 Murray, 1S98.) 



WHEN a man of unequivocal scientific eminence 

 lays aside the technicalities which have assisted 

 him along the path of important investigations, and 

 attempts to reveal as much as may be of his subject to 

 the wide public who cannot understand mathematical 

 processes, the result is certain to be at least interesting. 

 And especially is this so in the case of a subject at once 

 so fascinating and so perplexing as that of the tides. A 

 phenomenon of such evident significance in the economy 

 of the globe, of such important influence on the interests 

 of maritime communities, must necessarily have been 

 under observation from the earliest times. Naturally 

 the conscientious pre-Newtonian philosopher could not 

 do more than recognise a more or less indefinite con- 

 nection between the periodic alternations of sea-level 

 and the positions of the moon and sun. And if his mind 

 happened to be of that type which trusts more readily 

 to speculation than to accurate observation, his theories 

 were even less enlightened in a corresponding degree. 

 Even after the genius of Newton had laid a foundation 

 of rational hypothesis, the theory which remained with 

 little modification or development until a comparatively 

 short time ago, was one which on many essential points 

 was absolutely contradicted by facts. Now this is the 

 theory of which a rather inadequate description is in- 

 cluded in some popular works on astronomy, whose most 

 conspicuous failing in general is that they attempt to 

 cover afar wider range than is really practicable. How- 

 ever that may be, a short chapter in a work of this 

 character was practically the only place where inform- 

 ation on tidal phenomena was to be found in a popular 

 form, with -the exception, of course, of Lord Kelvin's 

 admirable popular lectures. In consequence, the subject 

 of the tides is perhaps the one about which, more than any 

 other, the most widespread misapprehension exists, even 

 among persons who are otherwise fairly well informed. 

 The present work therefore fills a manifest need, and 

 Prof. Darwin is certainly right in thinking " that there 

 are many who would like to understand the tides, and 

 will make the attempt to do so, provided the e.xposition 

 be sufficiently simple and clear." His dictum, that "a 



