BOOK NOTICES 63 



resources of the deep and the influences which affect them, will be 

 grateful to Mr. Johnstone for bringing together in convenient form 

 the results of much of the work recently accomplished in marine 

 science. The department of knowledge which endeavours to deal 

 with the productions of the sea from a quantitative point of view is of 

 comparatively recent origin, and even yet, as Mr. Johnstone's pages 

 undisguisedly show, has only reached the hesitating stage of infancy 

 though, to be sure, the healthy infant and of great promise. 

 This slowness of advance is in great part due to the exceedingly 

 complicated nature of the problems which the quantitative biologists 

 have set themselves, for obviously the seasonal fluctuations of 

 organisms and the distribution of marine creatures in general are 

 dependent upon physical causes, and on this account extended 

 hydrographical and oceanographical investigations have been 

 rendered necessary. With all those branches of study, with the 

 methods and results of quantitative marine biological research, and 

 with hydrography and oceanography in so far as they bear thereon, 

 Mr. Johnstone deals clearly and interestingly. Some of the results 

 are almost incredible. For instance, we are told that i cubic metre 

 of water from the Mediterranean Sea off Syracuse contains in all 

 2,425,665 drifting organisms, and that the number of haddocks in 

 the North Sea in the spring of 1905 was calculated at 180,239,000, 

 and we are enlightened as to the methods by which those approxi- 

 mate results are obtained. 



This, the main portion of the book, is preceded by a useful intro- 

 ductory part dealing with the apparatus and methods employed in 

 oceanographical research, with life in the sea, its distribution, 

 fluctuations, and general significance, and with the economic popula- 

 tion of the sea and the modes by which it is exploited. Part III., 

 on the general conditions of marine life, contains many results of 

 great interest. Thus Piitter's researches seem to indicate that many 

 marine animals Sponges, Holothurians, Copepods utilise as food, 

 not so much solid organic particles, as the inorganic carbon and 

 nitrogen dissolved in the sea water. 



Mr. Johnstone has brought together with great care and much 

 labour a guide to recent marine research indispensable to the general 

 biologist who, unable to devote special attention to the conditions of 

 life in the sea, yet wishes to keep abreast of advancing knowledge. 

 To say that the book belongs to the Cambridge Biological Series 

 is to vouch for the high standard of typography, paper, and 

 binding. 



We mention the following slips for the sake of future editions : 

 on p. 46. " minimum contraction " for " maximum contraction " ; p. 

 48, "ocean currents are deflected to the right" is ambiguous, 

 "west" would be clearer; p. 58, "mussels beds" for "mussel 

 beds " ; p. 312, " Luidia, a bottom-loving sea urchin " ! ! J. R. 



