October 29, 1903] 



^t^ATVRE 



619 



classes, and can only regret that it has been necessarily 

 rather compressed. The limits of space have forced the 

 author to deal briefly with the physiological inquiries 

 for which the Ciliata have provided such a wonderfully 

 fertile field. The work of Verworn and others upon 

 the nuclear functions by means of " protozoan vivisec- 

 tion," and the studies of Miss Greenwood in intra- 

 cellular digestion, are very shortly dealt with, while 

 the classical accounts by Maupas of the processes of 

 reproduction among the Ciliata deserve more expansive 

 treatment than they receive in Prof. Hickson's excel- 

 lent summary. Enough is given, however, of these 

 biological studies to illustrate the author's discussion 

 of the significance of the heterokaryote body, the in- 

 dividuality of the Infusoria after conjugation, and 

 the incidence of somatic death among them, with 

 which he prefaces his descriptive classification of the 

 whole group. 



The Foraminifera are dealt with in an article of the 

 highest distinction by Mr. Lister, whose powers of 

 lucid description, together with many original draw- 

 ings and photographs of first-class merit, allow the 

 rt ader to follow, perhaps for the first time with ease, 

 (lie intricacies of skeletal structure and life-history 

 found in this group. A unique value is given to this 

 section by the inclusion within it of Mr. Lister's own 

 researches into the remarkable phenomena of dimor- 

 phism in the Foraminifera, which he illustrates by a 

 complete account of the alternation of the microspheric 

 and megalospheric generations in the life-cycle of 

 Polystomella. This dimorphism, with other characters, 

 i-- followed through the various groups of Foraminifera 

 >o far as our present knowledge allows, and the facts 

 are summed in a concluding survey, to which is 

 appended a systematic classification and bibliography. 

 Mr. Lister lays stress on the importance of life-history 

 as evidence in the determination of phylogeny in this 

 i^roup, and this is becoming more and more evident in 

 the case of other groups also of Protozoa. As an 

 example of the questions of fundamental importance 

 u hich are likely to arise in the further study of these 

 life-histories may be noted the occurrence of the multi- 

 form condition especially in the microspheric gener- 

 ation, which Mr. Lister has ingeniously compared with 

 the repetition of ancestral form seen in the sexually 

 produced larva of the Cladoceran Leptodora, but not 

 in its parthenogenetically developed young. This 

 section marks a brilliant advance in description of the 

 Foraminifera, and Mr. Lister is to be heartily con- 

 gratulated upon it. 



The earlier pages of the volume are given to an 

 article by Prof. Farmer on the structure of animal 

 and vegetable cells, of which, short as it is, 

 nearly one-half is devoted to the discussion of 

 reducing divisions and to some other physiological 

 points. The problem of the structure of protoplasm 

 and of the resting nucleus is dealt with, on the whole, 

 perfunctorily, and is nowhere illuminated by reference 

 to the results of Fischer and others in connection with 

 the action of fixatives — results notably confirmed and 

 extended in this country by Hardy — which already 

 promise to remove these questions from the dust of a 

 microscopists' quarrel and place it on the stage of exact 

 physical inquiry. 



NO. 1774, VOL 68] 



PRACTICAL PHOTOGRAPHY. 



Carbon Photography made Easy. By Thos. Illing- 

 worth. Pp. 150. (London : IlifTe and Sons, Ltd., 

 1903.) Price IS. net. 



Portraiture for Amateurs without a Studio. By 

 Rev. F. C. Lambert, M.A, Part i. (Technical) and 

 Part ii. (Pictorial). Pp. iv+176. (London: Hazell, 

 Watson and Viney, Ltd., 1903.) Price, each part, 

 is. net. 



The Elementary Chemistry of Photographic Chemi- 

 cals. By C. Sordes Elhs, F.LC, F.C.S. Pp. 120. 

 (London : Hazell, Watson and Viney, Ltd., 1903.) 

 Price IS. net. 



Photography by Rule. By J. Sterry. Pp. 124. 

 (London : Iliffe and Sons, Ltd., 1903.) Price is. 

 net. 



PHOTOGRAPHY as now practised may be re- 

 garded from so many points of view, and pursued 

 for so many dififerent purposes, that it is desirable to 

 have treatises on special branches of it, such as those 

 now under notice. A considerable advantage of this 

 method of setting forth the facts and methods of photo- 

 graphy is that each section may be dealt with by one 

 who has paid special attention to it, and is able to 

 speak upon it with authority. 



Mr. Illingworth, for example, is a man whose 

 business very largely consists in the making of carbon 

 prints. His practical directions are, therefore, beyond 

 criticism, and we put up with, without a murmur, his 

 reference to " chloride, bromide, platinum, or other 

 commoner printing processes " because of the frank 

 and full way in which he describes the process in 

 which he is a specialist. His book would have been 

 better without the chapter devoted to the " Chemistry 

 of the Carbon Process," for here he has gone 

 outside his experience and his knowledge, and what 

 he has set down tends to error and confusion. The 

 discriminating student will discover this for himself, 

 but beginners cannot always separate the wheat from 

 the chaff, and it is for beginners that the book appears 

 to be chiefly intended. 



In a volume on the chemistry of photographic 

 chemicals one looks for a special knowledge of the 

 chemicals used in photography, but in the book before 

 us there is not much evidence of this. The author 

 appears to go out of his way to say that a " chemical 

 change theory " of the developable image " is the one 

 generally accepted at the present day." We very 

 much doubt it. But in the matter that deals with 

 the subject as set forth by the title, there are many 

 statements that need modification, if not correction. 

 Silver nitrate is doubtless the most important of all 

 "photographic chemicals," but only little more than 

 a dozen lines are devoted to its consideration. We 

 are told that when prepared by dissolving silver in 

 nitric acid hydrogen is evolved, and that when obtained 

 in the solid form, preferably by fusion, it is not likely 

 to be alkaline. Now fused silver nitrate often is alka- 

 line, and as to the equation showing hydrogen liber- 

 ated from nitric acid by the metal, the less said the 

 better. We are told that the oxidation of sodium 

 sulphite to sulphate by exposure to the air "is easily de- 

 tected by the crystals becoming powdery and opaque," 



