July 4, 1907 J 



NA TURE 



221 



result of a free intellectual construction. Naturally 

 we choose a scheme that with the simplest assump- 

 tions liarmonises with the greatest number of facts; 

 this is the reason why Euclidean geometry is that of 

 common life. As Mr. Withers points out, there is 

 very little chance of any change in this respect ; for 

 if a series of careful exjjeriments upon the stars were 

 to lead to triangles with the sum of their angles 

 different from :8o°, we should be more likely to give 

 up the hypothesis of the strictly rectilinear propaga- 

 tion of light than to adopt a non-Euclidean geometry 

 as that of "actual space." On the other hand, we 

 may some time gain experience of a new kind, pre- 

 senting itself as spatial, and requiring us to assume 

 more than three dimensions in space. 



Mr. Withers sensibly steers a middle course between 

 the extremes of pure empiricism and the a priori 

 hypothesis. That we cannot form any clear concep- 

 tion of four-dimensional space to which three-dimen- 

 sional space is related in a manner strictly analogous 

 to that in which a line is related to a plane in which 

 it lies, shows clearly enough that we cannot do 

 without experience; on the other hand, the definition 

 of a surface as a boundary between two adjacent 

 portions of space involves a concept which cannot 

 possibly be deduced from sense-experience, and the 

 recent theory of sets of points gives still more striking 

 examples. Mr. Withers's main contention is that 

 Euclid's parallel postulate is empirical, and this mav 

 be admitted in the sense that his argument requires; 

 at any rate, he shows the absurdity of some state- 

 ments of the a priori school. 



Die Reideitungsvorgciii ge bci den Pflaiizcn. Bv Dr. 



H. Fitting. Pp. xv-1-157. (Wiesbaden: J. F. 



Bergmann, 1907.) Price 3.60 marks. 

 .Although the phenomena of irritability in plants are 

 in a general way easily demonstrated, their elucid- 

 ation is a matter of extreme difficulty, and in spite of 

 the numerous original experiments that have been 

 devised, absolute proof in support of the explanations 

 offered is rarely possible. .V notable instance is fur- 

 nished by the debated question whether the percep- 

 tion of the stimulus of gravitv is localised in the tip 

 of the root. The experiments advanced by Charles 

 Darwin in favour of this view were speedily dis- 

 puted; Czapek's ingenious glass-shoe experiments, 

 although widely accepted as proof, have been ad- 

 versely criticised, and now more definite proof is 

 hoped to be obtainable by growing seedlings on a 

 rapidly revolving klinostat in such a position that the 

 tin and growing region situated on different sides of 

 the centre of rotation are subjected to centrifugal 

 force acting in opposite directions. The debatable 

 character of the arguments is one hindrance to a 

 study of the subject, to which is added the difficulty 

 of obtaining the literature, scattered as it is through 

 numerous journals and pamphlets. 



Dr. Fitting's monograph helps but little in the 

 matter of literature, as in many ca.ses space does not 

 even permit of stating the arguments put forward by 

 investigators, but as a critical guide to the estimation 

 of the various theories his book will be found very 

 useful. 



The book consists of three portions, dealing with 

 the occurrence of the phenomena, the path of trans- 

 mission of the stimulus, and the manner in which it 

 is transmitted. Owing to the absence of descriptions, 

 the first part is only suitable to the reader who has 

 a full acquaintance with the subject or is prepared 

 to look up the literature. The discussions of the 

 various paths by which the stimulus mav travel and 

 of the mechanism involved are the most instructive 

 parts of the book, and particular interest attaches to 



NO. 1966. VOL. 76] 



the sections on protoplasmic communications, on the 

 fibrillar structure in cells of the root-apex, and on 

 the electrical phenomena connected with stimulation. 

 Dr. Fitting has himself added materially to the facts 

 of irritability phenomena and their interpretation, so 

 that his opinions are extremely valuable, the more so 

 because he is a searching but unbiased critic. 



Birds and their Nests and Eggs found in and near 

 Great Towns. By G. H. Vos. Pp. xii-i-148; illus- 

 trated. (London : G. Routledge and Sons, Ltd., 

 n.d.) Price li. 

 To take birds' nests and their contents with the 

 camera is in every way a more satisfactory proceeding 

 than egg-collecting, and if the author of this little 

 volume succeed in aiding the new movement he ought 

 to obtain the gratitude of all bird-lovers — not to men- 

 tion the birds themselves. Two things are essential 

 in this pursuit : first, the capacity of " spotting " 

 nests, which seems to be an inborn art, incapable" of 

 being acquired otherwise, and, secondly, skill in mani- 

 pulating the camera. In the latter accomplishment 

 the author excels, but for the former he has had to 

 depend on a friend; and the combination of forces 

 has produced most satisfactory results. 



The numerous photographs of nests and eggs in 

 their natural sites are all that can be desired, and as 

 regards these no encomiums are too high. We wish 

 we could say the same with regard to the photographs 

 of the parent birds, which, we are told, are taken from 

 " characteristically stuffed typical individuals placed in 

 natural surroundings, illustrating as nearly as possible 

 the conditions under which they were observed." In 

 our opinion these " faked " photographs are thor- 

 oughly unsatisfactory, the birds being obviously stuffed 

 (whether "characteristically," in the sense in which 

 the author evidently uses the term, or otherwise), and 

 appearing ill at ease in their pseudo-natural surround- 

 ings. The book would be far better without them. 

 -As the nests, which include those of a considerable 

 number of species, were all observed within a radius of 

 sixteen miles from the City, beginners whose homes 

 are in large towns need not be deterred by lack of 

 material from following in the footsteps of the author, 

 to whom amateur photographers in general are in- 

 debted for showing how much can be done at a 

 comparatively small expenditure of time and money. 



R. L. 



Ki)istnp Organisations and Croup Marriage in Aus- 

 tralia. By N^rthcote W. Thomas. Pp. xyi-(-i64. 

 (Cambridge : University Press, 1906.) Price 6s. net. 

 Mr. Thomas has digested everything that has been 

 written on the .Australian natives. In this volume he 

 gives us a very useful resume of all the facts of their 

 complex social organisation, separating the attested 

 from the doubtful — a much-needed piece of work. The 

 account is interwoven with Mr. Lang's theory of .Aus- 

 tralian kinship and marriage evolution, perhaps the 

 most plausible hitherto advanced, though in the 

 matter of totemic origins it may encounter opposi- 

 tion. Mr. Thomas suggests some real improvements 

 in terminology — matrilocal instead of beena. matri- 

 linear and patrilinear, matripotestal and patripotesta! 

 — these should be generally adopted, as no doubt they 

 will. The author seems to be at his best in the dis- 

 cussion of such a vexed question as group marriage ; 

 the argument is closely reasoned, and brings out 

 several new points. There is an excellent index. The 

 book will be indispensable to anthropologists, and 

 sociologists generally will find it an admirable and 

 convenient text-book for the study of the beginnings 

 of social organisation. 



A. E. Cr.awley. 



