July i8, 1907J 



NA TURE 



267 



and the unknown cannot be exaggerated. For 

 example, if one may judge from the variation in yield 

 among existing varieties of wheat, an increase of lo 

 to 20 per cent, in the maximum yield is not beyond the 

 reasonable expectation of the raiser of new varieties. 

 This increase involves the cultivator in no extra ex- 

 pense to speak of, whereas if he obtained it by means 

 ol fertilisers or more intensive cultiva'tion, the added 

 cost might easily consume all tlie extra return for 

 the crop. 



In the creation of new varieties of horticultural or 

 agricultural plants the guiding principle in the past 

 has been selection. In many cases this has consisted 

 in the skilled observer picking out "mutations," new 

 forms which have arisen per saltuni and show some 

 essential and transmissible difference from the type. 

 In other cases a process of slow amelioration has gone 

 on through persistently breeding only from the best. 

 For example, the percentage of sugar in the sugar 

 beet has been doubled in about fifty years b}- select- 

 ing for seed purposes only those roots which were 

 richest in sugar, a little core having previously been 

 bored out for analysis. It is necessary, however, to dis- 

 tinguish here ; richness in sugar is a congenital condi- 

 tion of the root, transmissible with variations to its 

 descendants, whereas mere size or other temporary 

 factors due to culture cannot be so passed on and do 

 not in consequence form material for selection. Thus 

 it is probable that an immense amount of work that 

 has been done to improve cereals by sowing only the 

 largest or the heaviest grains, or, again, the grains 

 from the longest ears, has been wasted ; there is no 

 evidence of the permanent amelioration of any variety 

 bv this method. The advances have all been acquired 

 by "pure culture" methods; a desirable type of ear 

 Of grain is seen, and a pure strain is created by 

 propagating from that, alone. 



It is with these questions of mutation and selection 

 that Prof. Costantin's book mainly deals, but though 

 such methods have had the field very largely to them- 

 selves in the past, they are not likely to retain their 

 position in the future. Until recently the raiser of 

 new varieties was rather shy of cross-breeding; he 

 obtained thereby such an extraordinary and unstable 

 setof mixtures that it was only by a lucky accident he 

 could select anything tractable from it. Thanks, 

 however, to the Mendelian hypothesis, we are now 

 able to handle with some precision the varied hybrid 

 forms which result from a cross, and the work of the 

 Cambridge school of biologists, of Bateson among 

 sweet-peas, and of Biffen among wheats, has shown 

 what a remarkable practical tool Mendel has placed 

 in the hands of the plant-breeders. Mendel's work 

 has revolutionised the whole point of view, 

 and in consequence Prof. Costantin's book, which, 

 though dated igo6, contains no mention of Mendel 

 and his theories, is hardly of service to the plant- 

 breeder of to-day. Doubtless we may have to come 

 back to a consideration of many of the facts therein, 

 facts which lie outside the scope of Mendel's hypo- 

 thesis, but just at present the current is setting so 

 strongly the other way that Prof. Costantin's book 

 will not meet with much acceptance. 

 NO. 1968, VOL. 76] 



SCIENCE FOR ARTISTS. 

 Modern Painters. By John Ruskin. 5 vols. 

 The Stones of Venice. By John Ruskin. 3 vols. 

 Unto this Last, and Other Essays on Art and Political 



Economy. By John Ruskin. Everyman's Library. 



(London : J. M. Dent and Co., n.d.) Price is. net 



per volume. 

 A CHEAP edition of Ruskin's works, clearly 

 -'»• printed, and with the author's illustrations well 

 reproduced, is a boon which will be keenly appre- 

 ciated in many directions. The world of art already 

 owes a heavy debt to " The Stones of Venice " and 

 " Modern Painters," but for many years these have 

 been accessible to the young student only through the 

 agency of the public library or some such place. The 

 great critic, whose watchword was "truth," thus 

 failed to see the full fruits of his teaching. Now it 

 is possible for anyone to enjoy the benefit of his writ- 

 ings, and the training of an artist must be regarded 

 as incomplete until he has mastered, at least, the 

 principles of his calling as laid down by Ruskin in 

 "Modern Painters." 



It has always, ever since the days of ancient 

 Greece, been fully recognised that no representation 

 of the human form can be even passable unless it is 

 anatomically correct. Every muscle, every sinew, 

 must be in its proper place, and correctly propor- 

 tioned; even the attitude and expression of each figure 

 must be correctly fitted to the subject, or the result 

 will be unmercifully condemned. But how many a 

 landscape is defaced with impossible clouds, trees 

 which grow nowhere on this earth, and even rocks 

 and mountains such as no eye has ever seen. In 

 truth, nature has an anatomy as real as that of the 

 human body, and the man who knows turns from 

 such parodies with exactly the same feeling of con- 

 temptuous disgust as is inspired by a figure with 

 misshapen limbs, or poised in an impossible attitude. 



Misrepresentation of nature has been endured by 

 the public from ignorance bred by lack of observation. 

 As Ruskin says, it is not easy to discern the truth. 

 The eye has to be trained to see correctly, 

 and a picture should contain just that amount 

 of fact which would be visible in the circumstances 

 represented, and no more. It is useless for men who 

 would be regarded as scientific Philistines to urge 

 such things upon artists. Only the great ones would 

 listen for a moment, and they are just those who need 

 the advice least of all. They have always known, 

 more or less, how to combine truth of visible detail 

 with those qualities of breath and feeling which are 

 involved in the idea of a "picture." But the rank 

 and file too often palm ofif on ignorant buyers works 

 which are wrong in drawing, wrong in colour, and 

 ridiculous as representations of nature. 



No one can regard Ruskin as a mere man of 

 science, and he should command the attention of all 

 who aspire to be his brother artists. His magnificent 

 chapters on clouds, on plant forms, and on mountain 

 sculpture are admirable alike in conception and execu- 

 tion. They are an excellent beginning. An artist 

 who has studied them with care cannot but go to 



