November 3, 19 10] 



NATURE 



them. In these circumstances it is not to be wondered 

 at if the value of pruning in any form or degree 

 has come to be questioned by certain fruit-growers 

 and experimentalists, who have had very little diffi- 

 '.ttter to expose all parts of the tree to the sun and 

 t diminishing the crop. 



It still remains incontrovertible, however, that young 

 trees are benefited by a moderate degree of pruning 

 if this is carried out by intelligent operators possessing 

 rhe knowledge and experience necessary for the task. 



ach pruning is necessary for forming a proper 

 ■ oundation for the tree, for the removal of cross- 

 branches, and the thinning out of the centre in order 

 to better expose all parts of the tree to the sun and 

 air. 



This volume, prepared by the horticultural in- 



ructor for the Department of Agriculture, South 

 vustralia, under the direction of the Hon. Minister 

 : Agriculture, is issued for the purpose of teaching 

 the technique of pruning to fruit-growers having to 

 work under the climatic and economic conditions 

 prevailing in temperate Australia. The author's quali- 

 fications for teaching are clearly shown in his sensible 

 and pertinent remarks upon the facts on which the 

 l.eory of pruning is based, and his description of the 

 bjects the pruner seeks to obtain. Having instructed 

 the reader in these matters, he describes the opposite 

 effects of winter and summer pruning, the parts 

 of a tree, and their different values ; also the 

 forms of tree to be encouraged, and the best means 

 of developing fruit-bearing wood in place of foliaceous 

 but barren branches. He n(.'Xt passes to a descrip- 

 tion of the specific treatment of different kinds of 

 fruit, including apricot, plum, cherry, almond, peach, 

 apple, pear, quince, fig, orange, lemon, and loquat. 



There are 200 illustrations from photographs, most 

 of these being valuable as a means of explaining the 

 text, but others are inferior, and their omission would 

 not have detracted from the appearance of the volume. 



UNCONSCIOUS MEMORY. 

 Unconscious Metnory. By Samuel Butler. New 

 edition. With an Introduction by Prof. Marcus 

 Hartog. Pp. xxxvii+186. (London: A. C. Fifield, 

 Clifford's Inn, E.C., 1910.) Price 5^. net. 

 TT is probable that Butler will live in history as the 

 -*• writer of " Erewhon," but his more serious works, 

 dealing with what may be called the philosophical 

 side of biology, are still worth reading, and Mr. 

 Fifield's re-issue will be welcomed by many. The 

 volume under review consists partly of rather personal 

 polemic against Darwin, and partly of a further de- 

 velopment of Butler's views as expressed in his " Life 

 and Habit." These views may be summarised as 

 follows. 



It is a fact of hourly observation that practice makes 

 things easy which once were difficult (e.g., the play- 

 ing of a sonata), and even results in their being done 

 without consciousness of effort. It follows that the 

 fact of an intricate action being done unconsciously 

 is an argument for the supposition that it must have 

 been done repeatedly already. Now take the case of 

 NO. 2140, VOL. 85] 



a newly-hatched chicken, which pecks at once and 

 perfectly. How is this? It is because something in 

 the chicken remembers having pecked before, and 

 consequently knows how to do it. An individual is 

 not a new being ; it — or part of it — has existed in the 

 bodies of its parents. Thus heredity is memory. 

 Cells remember what they have done before, and 

 know how to do it again. 



This, followed to its conclusion, involves the attri- 

 bution of some kind of intelligence even to atoms. 

 Indeed, we can hardly avoid it. Atoms have their 

 likes and dislikes. Carbon and oxygen are sociable, 

 fluorine is reserved and stand-offish. " The distinc- 

 tion between inorganic and organic is arbitrary." 

 (This view is closely akin to that of Haeckel.) All 

 action is purposive and intelligent. When an organ- 

 ism develops a new quality, it is because the organism 

 has felt the need of it. Evolution is therefore 

 teleological from within ; differentiation of species, 

 and variations of all kinds, are not entirely due (or 

 as much as Charles Darwin supposed) to natural 

 selection. Here Butler follows Buffon, Lamarck, and 

 Erasmus Darwin. 



Mr. G. Bernard Shaw has said that Butler was, in 

 his department, the greatest English writer of the 

 latter half of the nineteenth century; and, though 

 he was only a dilettante, it is surprising how 

 illuminating and suggestive his ideas seem, even now, 

 thirtv or forty years after first publication. It is note- 

 worthy that Dr. Francis Darwin quoted him with 

 special approbation in his presidential address before 

 the British Association in 1908. 



Prof. Marcus Hartog furnishes a useful introduc- 

 tion, discussing Butler's whole work and his place 

 in the history of science. 



The first edition of " Unconscious Memory " was 

 reviewed in Nature, January 27, 1881. 



THE MAMMALS OF EUROPE. 

 Faiine des Mammiferes d'Europe. By Prof E.-L. 

 Trouessart. Pp. xvii + 266. (Berlin: R. Fried- 

 lander and Sohn, 1910.) Price 12 marks. 

 IN issuing an up-to-date descriptive catalogue of the 

 mammals of Europe Prof. Trouessart has conferred 

 a real and lasting benefit on zoological science, sincj. 

 owing to the great increase of species and races du 

 to modern methods of discrimination, the well-known 

 work of Blasius has long been practically useless. 

 Indeed, if the two works be compared, it might at 

 first sight be difficult to believe that they treat of the 

 same subject, so great has been the increase in the 

 last few vears in the number of recognisably distinct 

 forms, and so extensive the changes in nomenclature. 

 Nowadays views differ — and will probably continue to 

 differ — SiS to the limitations of species and races; but 

 Dr. Trouessart appears inclined in most cases to use 

 the former term in the most restricted sense. Justify- 

 ing himself in doubtful instances by the dictum of 

 Desmarest that " il est plus misable de trop reunir que 

 de trop diviser," he might, if we remember rightly, 

 have supported an opposite view by a statement of 

 Huxley to the effect that it is more important to re- 



