2o6 



NATURE 



[October 14, 1920 



lands. As the lands are elevated, the weather- 

 ing becomes more active and the high places are 

 brought down to the sea. The waters are thus to 

 a certain extent displaced, and perii)dically flood 

 more or less of the lands. Every now and then, 

 when the lands are largest, highest, and driest, a 

 cold period sets in and disarranges the whole 

 organic world. During these critical times the 

 earth is scenically grand, and the struggle for 

 existence unusually inten.se. The over-specialised 

 types give place to smaller, less specialised, more 

 plastic tyjjes. The unadaptive types become ex- 

 tinct, or are pressed into corners and refuges. 

 Some adaptive stocks find relatively easy haunts, 

 as in the sea, but from such there evolves no great 

 mentality. The highest organisms, with the 

 greatest mentality, have evolved on the land, 

 "where the struggle for existence is fiercest, be- 

 cause of the constant necessity of adaptation to an 

 environment subject to intense changes. Organic 

 supremacy is attained only through constant 

 vigilance. " 



In the third lecture Prof. L. L. Woodruff gives 

 a clear and critical account of the various sugges- 

 tions that have been made in regard to the origin 

 of organisms, cautiously favouring the uniform- 

 itarian idea that they arose from not-living matter 

 upon the earth. 



Of great interest is the fourth lecture, in which 

 Prof. R. S. Lull discourses on "the pulse of life," 

 attempting to link up cause and effect; "to find 

 those forces which are responsible for the more or 

 less rhythmic accelerations of evolution shown by 

 the fossil record. The main cause is found to be 

 climatic change, which in turn has as a chief con- 

 trolling factor earth-shrinkage and the consequent 

 warping of the crust." In a very fresh and sug- 

 gestive way. Prof. Lull discusses some of the 

 crises in organic evolution and their physical cor- 

 relates. Thus he deals with the establishment of 

 the lime-secreting habit, the origin of vertebrates, 

 the emergence of terrestrial vertebrates, the evolu- 

 tion of the terrestrial foot, the origin of reptiles, 

 the establishment of warm-bloodedness, the ap- 

 j>earance of birds and mammals, man's arboreal 

 apprenticeship, his descent from the trees, and his 

 subsequent ascent far above the level of climbing. 

 He.submits a very striking curve to show the 

 correspondence between the -pulse of life and the 

 heavings of the earth's broad breast. To mention 

 a concrete factor, he shows how aridity probably 

 affected the evolution of dinosaurs. 



In the fifth lecture Dr. Ellsworth Huntington 



deals with the influence of climate on civilisation. 



Human progress depends, he says, upon three 



resources, and constitutional energy. But climate 



NO. 2659, VOL. 106] 



has a great influence on each of these, especially 

 the last — a thesis which the lecture graphically 

 illustrates. Some of the great steps in civilisation 

 are discussed, and likewise some of the relatively 

 recent climatic changes ; the problem is to correlate 

 the two. The author admits that, so far as inherent 

 mental capacity is concerned, climate is in one 

 sense a minor factor; that it is more important as 

 regards material resources, but is far from being 

 the sole factor ; and that even when energy is con- 

 sidered, the effect of climate may readily be neu- 

 tralised by several other factors, such as lack of 

 resources or lack of ability. But the point to be 

 emphasised is that climate is one of the great 

 factors which must be reckoned with in any 

 attempt to understand the history of civilisation. 



The five essays are at a high level, the authors 

 evidently giving of their best. There are a number 

 of vivid illustrations, and Prof. Lull's "pulse of 

 life " diagram makes a deep impression. We 

 strongly recommend the book to serious students 

 as a notable contribution to the study of the 

 various modes of the great process of becoming. 



J. A. T. 



Fertilisers and Parasiticides. 



Chemical Fertilisers and Parasiticides. By 

 S. Hoare Collins. (Industrial Chemistry.^ 

 Pp. xii + 273. (London : Baillitre, Tindall, and 

 Cox, 1920.) Price los. 6d. net. 



MR. COLLINS has followed up his book on 

 plant products by another on chemical 

 fertilisers and parasiticides, of approximately the 

 same size and intended for the same kind of 

 reader. The book gives a good general account 

 of fertilisers, and it includes numerous tables of 

 data which will be found useful to the specialist. 



Artificial fertilisers are of great interest to 

 British chemists, as they were first used in this 

 country and for many years the industry remained 

 in British hands. The beginning was made in 

 1843, when Lawes took out his first patent for 

 the manufacture of superphosphate; the industry 

 developed greatly when the Chilean deposits of 

 nitrate of soda began to be worked largely by 

 British enterprise, and when sulphate of ammonia 

 was recovered from coal-gas and from coke-ovens. 

 It underwent further expansion in the 'eighties, 

 when Wrightson showed the value of basic slag, 

 followed in the 'nineties by the demonstrations of 

 Dobbie, Gilchrist, Somerville, and Middleton. 

 Only one important section has remained outside 

 British hands — the potash fertilisers, which were 

 formerly controlled by German interests, but now 

 will be worked by the French companies. 



Mr. Collins deals mainly with the sources and 



