NOTICES OF BOOKS. xliii 



elements, and sense illusions proper where the ideas excited by association permanently 

 outweigh the direct sense impressions. Next comes Successive Association, (i) immediate, (2) 

 mediate, a section which Wundt is constantly elaborating ; cf. Phil. Stud., x. , 2, where he 

 refers the experience of an idea, or memory image, called up by the unnoticed scent of a flower, 

 quoted by Jerusalem as a case of an "unconscious'' middle factor, to the category of an 

 unrecognised, but not unconscious, factor — dimly perceived, but not apperceived in consciousness. 



fie next discusses the "intellectual, conscious processes," which include concepts, 

 judgments, and apperceptive connections of ideas. 



The complex affective processes are summarised as Emotions, and the expression of 

 the Emotions — Instinctive and Voluntary Action — with a concluding chapter on Immortality, 

 Phrenology, and the Principles of Psycho-physical Parallelism. It is impossible in the limits 

 of a review to give a competent outline of the contents of this book, one falls between the 

 catalogue and the encyclopaedia. The physiological sections are the most convincing, and 

 command respect for the profundity and grasp of Wundt's treatment in comparison with the 

 superficial handling of some later writers. 



A translation from the hands of Prof. Titchener carries its own recommendation. He is 

 so strong on the point of " psychological nomenclature " that he doubtless has good reasons 

 for introducing such unfamiliar terms as "clang," "clang character," "clang compound," 

 "deception of judgment," "just noticeable difference," etc. But in lecture vi. it is difficult to 

 subscribe to the rendering of " farblos " by "bright," "brightness" (throughout the chapter). 

 Why not a-chromatic f The division into numbered sections is a distinct help towards 

 acquaintance with the subject-matter. 



F. A. Welbv. 



An Introduction to the Study of Seaweeds. By George Murray, F.R.S.E., F.L.S. London: 



Macmillan & Co., 1895. 



Mr. Murray's name is well known in connection with Algae from his researches published 

 in Phycological Memoirs (pi which he is editor), his Catalogue of the Marine Algce of the 

 West Indian Region, and other works. 



The book before us opens with an introduction of thirty-three pages, dealing shortly 

 with the history of Phycology, with geographical distribution of seaweeds and the causes 

 affecting it, and includes hints on collecting. This is followed by a short Bibliography ; and 

 the remainder of the volume is occupied with the general morphology of the seaweeds. 



For reasons of convenience the Phaeophyceae are described first, but it seems rather a 

 pity that the sub-classes should be numbered in the order adopted, viz., Phaeophyceae, 

 Chlorophyceas, Diatomaceae, Rhodophyceaa, Cyanophyceae. 



The results of some of the researches recently published in the Phycological Memoirs are 

 incorporated in the descriptions, and several of the genera described and figured are uncommon 

 ones, and information about them difficult to get. These features, and also the large number 

 of excellent illustrations, contribute largely to the value of the book. There are eighty-eight 

 figures, representing habit, microscopical structure, etc., besides eight coloured plates. With 

 these numerous illustrations it is hardly fair to ask for more, but one would have liked one 

 figure of the conjugation of planogametae, to compare with the fertilisation of Fucus. 



The Bangiaceas are, no doubt rightly, excluded from the Rhodophyceas (p. 248), but a 

 comparison of Porphyra with Prasiola might, perhaps, have been added by way of a suggested 

 relationship. 



The descriptions are mostly concise, but a few statements are made in rather too 

 general terms to be of much service ; thus (on p. 113, last line), some of the Sphacelariaceae, 

 when attacked by Chytridiaceae, ' ' present appearances which have been a source of error in 

 their interpretation ". This rouses one's curiosity without gratifying it, but it is perhaps useful 

 as an incentive to research. The following also seems rather too vague to be suitable for a 

 manual for students: "A certain resemblance of this remarkable body to the Volvocineae 

 (fresh water) suggests inevitable speculations which may easily be made too much of". 



In perusing the book one comes across occasional misprints, which will, no doubt, be 

 corrected in a future edition. Thus, on page 190, the size of unusually large Diatoms is 

 given as a third of a micro-millimetre for fresh water forms, and about three micro-millimetres 

 for marine forms. Taking a micro-millimetre in the sense in which it is used by botanists 

 and zoologists, this would make the length of these Diatoms about a hundredth part of the 

 real value. 



A book on Algae has long been a desideratum, and all students will feel indebted to the 

 author for removing many of the difficulties which have hitherto hedged round the study of 

 some of the most interesting groups of the Vegetable Kingdom. 



H 



