October 20, 1892] 



NATURE 



583 



circumstances permit, of the principles and practice 

 of the progressive gardener. This is very obvious to 

 those conversant with the state of commercial horticul- 

 ture, as contrasted with the condition of the correspond- 

 ing department of agriculture, and it will be brought 

 home to the thoughtful reader by the perusal of some of 

 Mr. Paul's pages. It is interesting, too, to see that mat- 

 ters at which some minds would still be inclined to scoff 

 as unpractical, or which they would regard as mere means 

 of affording agreeable recreation, are the very depart- 

 ments in which the greatest practical successes have 

 been achieved in the past, and which are of the best 

 augury for progress in the future. 



Biologically speaking, Mr. Paul has been not only a 

 keen observer but a careful experimenter on a very large 

 scale, and over a very long period. It is true his experi- 

 ments have not been and could not have been made with 

 the exact accuracy which we expect in the laboratory, but 

 they have been made under conditions far more akin to 

 those which occur in nature. Moreover, they have been 

 made, although with a definite aim, yet without reference 

 to any particular theory. The reader will accordingly 

 find in these pages records of work and inferences from 

 carefully planned experiments directly bearing on many 

 subjects now attracting the attention of naturalists, such 

 as hereditary transmission, variation from seed or from 

 bud, selection, fixation, close fertilization, and the various 

 degrees of cross-impregnation. Incidentally these sub- 

 jects receive illustration in many chapters of Mr. Paul's 

 book ; but the address on " The Improvement of Plants," 

 which was read in 1869 before the provincial meeting of 

 the Royal Horticultural Society at Manchester, contains 

 a summary of Mr. Paul's views on these subjects, which 

 we strongly commend alike to the notice of naturalists 

 and of agriculturists. 



It is very interesting to compare what he says about 

 selection and variation in plants, such as the Camellia, 

 the Chinese Primrose, or the Hollyhock, which are the off- 

 spring of what we regard as pure species, with the corre- 

 sponding processes in the Rose, the Pelargonium, or the 

 Chrysanthemum, which are veritable mongrels. In this 

 connection we may in passing allude to the power which 

 the gardener has, of course within limitations, of creating 

 new forms. The orchid cultivator, for example, inferred 

 parentage of certain hybrids met with in a wild state, 

 but he has since proved the correctness of his inference 

 by actually producing in his orchid-house many of the 

 same forms that occur in the forests of the tropics. 

 Another very striking case (not specially alluded to by 

 Mr. Paul) is the production and development of what 

 are known as tuberous Begonias. These have been 

 evolved by the art and patience of the gardener within 

 the last quarter of a century from repeated crossing 

 between certain Andean species of Begonia and their de- 

 scendants. The result is the establishment of a race so 

 totally distinct from anything yet known in nature as 

 would justify a systematic botanist in forming a separate 

 genus for their reception. Many an accepted genus is 

 based upon less important points of distinction than those 

 which characterize the tuberous Begonias, and which, 

 indeed, have been gathered together by Fournier under 

 the genus Lemoinea. The degree of permanence of this 

 artificially formed genus is, of course, unknown ; but we 

 NO. I 199, VOL. 46] 



do know already that the peculiarities are reproduced 

 from seed, and that each year the plants are, as the 

 gardeners say, becoming more "fixed." We have 

 alluded to these as illustrations of the kind of work upon 

 which Mr. Paul has been engaged for half a century. 

 They may be taken as examples of the material he has 

 gathered together in this book, which is not merely pre- 

 sented for the delectation of the ordinary lover of flowers 

 or the profit of trading horticulturists, but is also cal- 

 culated to increase the productive resources of the coun- 

 try, as well as to forward the progressive development 

 of our knowledge of the natural history of plants. 



As a further illustration of Mr. Paul's method we cite 

 in conclusion a passage which will, we think, justify us 

 for recommending to scientific readers the perusal of a 

 book which they might be disposed, from its title, to 

 think had little in it to interest them. " My experience 

 in selecting, hybridizing, and cross-breeding tells me 

 that he who is seeking to improve any class of plants 

 should watch narrowly and seize with alacrity any devi- 

 ation from the fixed character, and the wider the 

 deviation the greater are the chances of an important 

 issue. However unpromising in appearance at the outset, 

 he knows not what issues may lie concealed in a variation, 

 sport, hybrid, or cross-bred, or what the ground newly 

 broken is capable of yielding under careful and assiduous 

 cultivation. If we would succeed in this field we must 

 observe, and think, and work. Observation and experi- 

 ment are the only true sources of knowledge in nature, 

 and while observing and experimenting we should above 

 all things guard against prejudices." 



Maxwell T. Masters. 



LIFE IN MOTION. 



Life in Motion; or. Muscle and Nerve. By John Gray 

 McKendrick, M.D., F.R.S. (Adam and Charles 

 Black, 1892.) 



UNDER this title Prof McKendrick gives us the gist 

 of six lectures delivered by him during last 

 Christmas holidays to a juvenile audience at the Royal 

 Institution of Great Britain ; and, judging from this little 

 work, it is evident that no pains was spared by him to 

 render these lectures as instructive and interesting as 

 abundant illustrations and experiments could make them. 

 In presenting these lectures to the public in book form 

 he places us under an obligation gratefully to be acknow- 

 ledged, for professional physiologists stand alone amongst 

 their colleagues in other departments of science in their 

 disdain of any attempt at the production of attractive 

 and simple scientific literature. In very pleasing sympa- 

 thetic style the reader is introduced to the world of 

 motion and to the special motions of the living muscle. 

 He is shown how the movements of a muscle are recorded 

 by the physiologist, and the apparatus used for its stimu- 

 lation. Artificial tetanus is described, the muscle sound 

 and its elasticity referred to, and a perhaps too short 

 description given of amoeboid and ciliary motion. The 

 physiology of the nerve is then discussed, and the pro- 

 duction of heat in muscle. In the fifth lecture is a short 

 account of the sources of muscular energy, a comparison 

 is drawn between a muscle and the steam-engine, and a 

 comparatively detailed account of muscle fatigue is given. 



