43^ 



NATURE 



[March io, 1898 



physica,! investigators, accompanied by numerous pleasing 

 portraits. A steel-plate portrait of Mr. J. W. Svv'ann heads 

 this section. 



Thesecpnd Directory contains "a complete record of 

 all the industries directly or indirectly connected with 

 electricity and magnetism, and the names and addresses 

 of manufacturers in Great Britain, India, the Colonies, 

 America, the Continent, &c." Every means has been 

 taken to facilitate reference, and to make the Directory 

 of service to all who are concerned with electrical 

 industries. 



A Flower Hunter in Queensland and New Zealand. By 

 Mrs. Rowan. Pp. xiii + 272. (London : Murray, 

 1898.) 

 This book is one to be laid down with regret, so brightly 

 does the authoress tell of very varied scenes and ex- 

 periences, and so easily is the reader carried along with 

 herthrbugh- them. There are few books of travels in 

 which the fascination of the tropics to a naturalist is so 

 evident, or that would more strongly arouse the desire to see 

 for oneself what is here so well described. But the other 

 side of the shield is no less vividly placed before the 

 reader, and the price at which alone the pleasures of 

 tropical travel can be bought can be well realised from it. 

 Old travellers will find their experiences recalled, and 

 wiir bear witness to the accuracy of Mrs. Rowan's de- 

 scriptions alike of the beauties and of the discomforts of 

 the tropics, and will recognise that the latter are expressed 

 in no overstrained terms. There are rriany interesting 

 references to the earlier history of the Colonies, and others, 

 equally interesting, to points in natural history, though iti. 

 a. few of the latter the want of technical knowledge shows 

 itsdf. Many and wonderful as are the powers of ants, 

 observed in and authenticated from all parts of the world, 

 we should have hesitated to believe about the nests of the 

 green ants of Queensland, that " leaves and flowers are 

 spun together by spiders that the ants keep for the pur- 

 pose." ,Mr. Saville-Kent's statement that he has observed 

 the ants use their own full-fed larvae to supply the silk 

 required for spinning the leaves together, affords an 

 explanation sufficiently curious, but more in accordance 

 with what we should expect. Numerous excellent views 

 add to the attractiveness of the volume. It deserves, 

 and will doubtless receive, a welcome from those interested 

 in tra.vels and natural history. 



Introduction to Chemical Methods of Clinical Diagnosis. 

 ■■ By D. H. : Tappeiher (Munich). Translated from ; the 

 sixth -Germai;! edition, with an appendix on micro- 

 biological - methods of diagnosis, by 'Edmond I. 

 : McWeeney, . M.A;, M.D. • (Roy. Univ. of Ireland), 

 Professor of Pathology and Bacteriology C.U. Med. 

 ^ Sch., &c. Pp. vii:-|- 152.' Figs. 22. (London: Long- 



rrians. Green, and Co., 1898.) :. . ; 



The little book before iis consists of two parts^the first, 

 chemical ; the second,' what' the. author calls micro- 

 biolpgical. . The term micro-biological is an accurate 

 one, and includes the usual bacteriological work on the 

 one hand, and the examination of blood corpuscles and 

 the morphological elements of the secretions on the other. 

 Any system of classification — and one must have some — 

 has its disadvantages : the present one seems to work 

 very well. 



The book is well up to date, serum diagi^sis and the 

 chemical examination of the gastric contents being con- 

 tained in it. We think under the chemistry of the urine 

 a method for the quantitative estimation of urea and 

 uric acid ought to have been included. As far as we are 

 aware, there is no book in English of such small bulk 

 which contains so complete an account of chemical and 

 bacteriological or microbiological diagnostic methods. 

 It will not, of course, compete with the larger books on 

 this subject, as, for instance, von Jaksch, but will doubt- 

 less have a sale, and deserves it. F. W. T. 



NO. 1480, VOL. 57] 



LETTERS TO THE EDTTOR 



\_The Editoj- does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 y. to return, or to conespond with the writers of, rejected 

 . manuscripts intended for. this or any other part of Nature. 

 No notice is taken of anonymous communications.'} 



Five-fingered Crab. 



During a recent visit to the museum at Dover, I noticed in 

 the case allotted to the Crustacea a remarkable instance of mal- 

 formation affecting the right pincer of a. half-grown specimen of 

 our common edible crab {Cancer pagurus) ; and not recollecting 

 to have seen the like either figured or described, I venture to 

 think the publication of the subjoined sketch, together with a few 

 words of explanation, may prove of interest to the readers of 

 Nature. 



A glance at this sketch will show that there are three complete 

 subequal movable -fingers or dactylopodites, numbered i, 2, 3. 

 Of these, number 3 clearly corresponds to the single movable 

 finger of the normal pincer, numbers i and 2 being super- 

 numerary and articulated close together upon an elevation of 

 the hand (propodite), which is much thickened in this region. 

 The two remaining fingers (indices) are immovable. Number 4 

 is very much the shorter of the two, number 5 being quite com- 

 parable in size to either of the three movable digits. Judging 

 from its size and the spot whence it emerges from the hand, the 

 larger index (5) represents the immovable finger of the normal 

 pincer ; but its toothed edge is directed, not towards the normal 

 finger (3), but towards the supernumerary finger (i). The 

 smaller index, finger (4), on the contrary, has its biting margin 

 turned towards the biting margin of the normal movable finger 



(3), and in all respects, except size and point of origin, corresponds 

 exactly to the immovable finger of the normal pincer. When 

 the movable digits are closed, number i passes on the under side 

 of 5, number 2 on the upper side of 3, and number 3 shuts 

 directly upon 4. 



I am only acquainted with records of two cases of malforma- 

 tion in crabs' claws resembling this specimen in the Dover 

 Museum. - One of these is figured and described by Mr. Bateson 

 {Materials for. the Study of Variation, p. 530, No. 815 ; also 

 Proc Zool. Sac, 1890, p. 581); the other by M. Senechal (t??///. 

 Soc. Zpol. France, 1888, p. 123). In the former, however, the 

 supernumerary movable fingers numbered i and 2 in the figure 

 of the Dover specimen are represented by a single dactylopodite, 

 'which, nevertheless, shows its double nature by being divided at 

 the tip and furnished with two rows of teeth along its biting edge. 

 In the example observed by Senechal, on the contrary, there are 

 three complete movable digits arranged apparently very much as 

 in the specimen here described and figured ; but the process 

 from the propodite (hand) is represented by a broad plate con- 

 sisting of three only partially separated indices. ' ' 



February 27. R. I. PococK.' 



Dew and Absorption, 



I AM engaged on some daily experiments with a view to 

 measure dew as rain in lineal inches. At present, however, I 

 cannot distinguish between dew and absorption. 



I filla small cylinder (A) of tinned iron*— a tobacco canister — 

 to within about i inch of the top with garden soil, dry it at 212'* 

 F., weigh, expose it over-night, and re-weigh at 9 a.m. before 

 the sun comes on it. 



I now purpose to expose another similar tin (B) with ten cir- 

 cular holes pierced near its rim, and covered with a horizontal 

 glass plate. 



