;02 



NATURE 



[March 29. 1894 



on the east side of tropical Africa. It is said that in the 

 northern province of Sindh, whose vegetation was first 

 made known to science by Griffith, more than nine-tenths 

 if the plants, on a rough estimate, are indigenous in 

 Africa. At least one-half of these are common in Nubia 

 or Egypt. 



It is interesting to take for example the genus Psychoiria, 

 possibly the most difficult genus of the very large and 

 difficult natural order to which it belongs. In Hooker's 

 " Flora " there are 52 species, of which only 4 (Mr. Nairne 

 has only 2) are found within the Bombay Presidency. 



In conclusion, we may say that it is evident that the 

 author has taken a good deal of pains over the book, 

 but from a scientific point of view it is painfully incom- 

 plete as a conspectus of the plants of the district to which 

 it relates. 



THE PARASITIC THEORY OF THE CAUSA- 

 TION OF MALIGNANT TUMOURS. 



Cancer, Sarcoma, and other Morbid Growths coftsidered 

 in Relation to the Sporozoa. By J. Jackson Clarke, 

 M.B.Lond., F.R.C.S. (London : Bailliere, Tindall, 

 and Cox, 1893.) 



IT is perhaps not to be expected that in the present 

 state of our knowledge of the relation of lower 

 animal parasites to morbid growths any very definite 

 opinion can be given on certain of the points raised in 

 the small monograph now under review, and, especially, 

 as to the accuracy of the opinions put forward. 

 Indeed we imagine that many readers, after surveying 

 with interest the arrangement and character of the 

 work, will come to the conclusion that whether the 

 theories advanced by the author are ultimately ac- 

 cepted or not, he has certainly not brought forward 

 sufficient evidence in support of his thesis, and that 

 had the energy and skill expended in polemical dis- 

 cussion and theoretical statement been brought to 

 bear in carrying out more extended observations 

 and the accumulation of facts, a very large amount 

 of definite information might have been contributed to 

 this very interesting subject. The interpretation put on 

 the observations of others, and didactic assertion, can 

 never be accepted in lieu of accurate observations, and a 

 mere statement as to the inaccuracy of the work of the 

 older observers, unless it is backed by prolonged in- 

 vestigation and accurate description, can never take 

 the place of such older work. 



After a careful perusal of the book now before us, and 

 with the above reservations, we feel justified in stating 

 that for those who wish to obtain a general outline of the 

 subject treated, the abstracts and references given by 

 the author will render this a comparatively easy task. 

 As regards the original portion of the work, one cannot 

 but feel that the author goes considerably beyond 

 his proof in assuming that pathologists cannot obtain 

 results similar to his — first of all, because they have not 

 familiarised themselves with the newer methods of 

 research, and secondly, because they have not " realised 

 the protean characters of the sporozoa " ; for, as the 

 author himself points out, a large number of workers, 

 some of them skilled histologists and trained biologists 

 and pathologists, have been laboriously engaged in trying 

 NO, 1274, VOL, 49I 



to set at rest some of the questions of which he so 

 light-heartedly disposes, but with which no evidence of 

 his own capacity to deal is offered in this original part of 

 the work. In some cases the drawings certainly do not 

 bear out the descriptions given in the text, whilst in 

 others few observers will be able to accept the somewhat 

 diagrammatic representations made to do duty as 

 illustrations, as being anything more than familiar de- 

 generative appearances seen through the eye of a some- 

 what partial observer. It appears to us to be a mistake 

 for any one to try to make facts fit into theories ; a 

 far more profitable occupation is to make theories accord 

 with facts. Again, some of the author's observations 

 may be accepted as accurate in themselves, but it is 

 difficult to see what bearing they have on the existence 

 of a causal relationship between the lower animal para- 

 sites and malignant tumours. That some such relation- 

 ship does exist is daily becoming more probable, but the 

 evidence accumulated up to the present, in spite 

 of the great amount of work that has recently been 

 done, is still but scanty, and it remains for workers to 

 follow out carefully and accurately the various " para- 

 sitic " forms that have been described, and to learn 

 something more of their mode of origin, life-history, and 

 ultimate destiny, before they can begin to build up 

 elaborate theories on the relation of these organisms to 

 morbid growths with any well-grounded hope that such 

 theories will have anything more than an ephemeral 

 existence. 



OUR BOOK SHELF. 



The Fauna of the Deep Sea. By Sydney J. Hickson, 

 M.A., D.Sc. (London : Kegan Paul, Trench, Triibner^ 

 and Co., Limited, 1894.) 



This little volume forms one of the " Modern 

 Science " series edited by the Right Hon. Sir ]► 

 Lubbock, Bart. It treats of a very interesting subject, 

 which for the last twenty-five years has attracted the 

 attention and engaged the service of many biologists. 

 Great though the contributions of our American and 

 French confreres have been towards its elucidation, yet 

 the long series of splendid volumes of our own Challenger 

 reports will stand as a proof of what this country has 

 done in this direction ; nor in writing this do we forget 

 for a moment the fact that many of the Challenger re- 

 ports were written by the sons of other nations besides 

 our own. With these reports and those by Agassiz on 

 the " Voyages of the Blake" our author certainly had 

 abundance of material for his sketch of the subject, for 

 he pretends to nothing more. He gives us a short 

 history of the deep-sea investigations, going back some 

 fifty years ago, to the time of Goodsir's haul in Davis 

 Straits, to Dr. Wallich's bringing up star-fish from some 

 1260 fathoms of depth, and so till he tells of the as 

 yet unfinished researches off the eastern slopes of the 

 Pacific Ocean by the Albatross, and those in the Indian 

 ocean by H.jVI. hivestigator. 



No doubt it was a difficult task to crowd into sixteen j 

 pages even a precis of such a mass of facts, and yet we \ 

 think it might have been improved had the author looked 

 into a volume, from which as far as we can judge he does 

 not quote, by Wyville Thomson, on " The Depths of the 

 Sea." The second chapter, on the physical conditions of 

 the Abyss, is well written. Might not the pelagic algae, , 

 which are sometimes to be found covering the surface 

 for miles, play a more important part than is seemingly 



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