2 8 



NA TURE 



[November 14, 1901 



and filariasis, and of the means of guarding against 

 them. The authors recognise in Mauritius only the types 

 of fever quartan, tertian and restivo-autumnal, and 

 have proved Anopheles costalis to be the definitive host 

 of their parasites in that island. Three species of Culex 

 C. anxi/er, C. alhopiclus, C. taeniatus — were shown to 

 be incapable of infection by parasites of human malarial 

 fever. Anopheles niaurilianas also appears to have no 

 relation to human malaria. The chapters on classifica- 

 tion, morphology, anatomy and biology add but little to 

 the literature of these subjects. In the present state of 

 our knowledge of the ;ctiology of malaria and filariasis 

 a more careful description of the minute anatomy of the 

 organs of the adult insect would have been extremely 

 useful ; probably difficulties in the preparation of com- 

 plete and perfect sections have prevented the authors 

 giving minute histological details. Descriptions of such 

 important structures as the membranous portion of the 

 pharynx, of the sali\ary receptacle, and of the muscles 

 attached to them, and, in view of the importance of the 

 recent discoveries of the presence of filarial larva; in the 

 labium of the proboscis, the relations and histology of 

 this organ especially, should have claimed the attention of 

 these naturalists. The spermatheca of the female insect 

 is not referred to. 



The authors are evidently not acquainted with the 

 structure of the parts of the proboscis. The salivary 

 duct is described as uniting the pharynx to the 

 oesophagus. Careful histological preparations show that 

 this is far from correct ; the salivary duct traverses the 

 neck and head below the cesophagus and pharynx, and, in 

 the region of the common origin of the mouth-parts from 

 the head, the duct opens into the salivary receptacle — a 

 chitinous trumpet-shaped organ with a wide membranous 

 proximal end into the n:iddle of which the salivary duct 

 opens itself ; while the narrow distal end is applied to the 

 upper end of a groove — the salivary canal — which runs 

 along the whole length of the hypopharynx. 



The cells of the epithelium of the stomach are de- 

 scribed as : — (i) I.arye spherical cells, with protoplasm 

 not stained by carbol-thionin, while the nuclei stain pale 

 rose-colour and the nucleoli violet. These are said to be 

 of lymphocytic nature. (2) Small spherical cells, with 

 a deep violet-staining nucleus, and protoplasm which 

 centrally stains with difficulty while the periphery is 

 deeply stained. These the authors consider to be diges- 

 tive in their functions. 



The epigastric glands of the larval stage, eight in 

 number, surrounding the anterior part of the stomach, 

 and the dialysing tube or membrane in the stomach wall, 

 are considered as playing an important part in the diges- 

 tive functions of the carnivorous larva. 



With regard to filariasis, the authors apparently found 

 only/', nocticrna in the blood of the people of Mauritius 

 where elephantiasis also occurs, and they have been able 

 to trace the complete life-history of the larval stage of 

 this nematode in the thoracic muscles of Culex cinxi/er. 



The authors do not appear to have recognised the 

 presence of malarial parasites in the blood of native 

 children, and hence do not refer to segregation of 

 Europeans as a preventive measure. " Eviter les 

 Anopheles" is their advice, and they uphold the opinions 

 of Ross and others that, although, perhaps, absolute ex- 

 NO. 1672, VOL. 65J 



termination of the insects will prove impossible, even in 

 small areas, yet their numbers may, by the application of 

 inexpensive and practicable means, be easily reduced to 

 an almost harmless minimum. They rely chiefly on the 

 use of culicicides, particularly of petroleum, and of 

 culicifuges, such as terebinthene and naphthalene. 



H. E. A. 



OUR BOOK SHELF. 



'' Disease in Plants. By H. Marshall Ward, Sc.D., 

 F.R..S., Professor of Botany in the University of 

 Cambridge. Pp. xiv -I- 309. (London: Macmillan 



J and Co., Ltd., 1901.) Price "js. bd. 



This is a very suggestive work, and the clearness with 

 which Prof Ward has treated a difficult and complex 

 subject will ensure for his book a welcome on the part of 

 \ the specialist, not less than that of the wider public to 

 whom the volume is more immediately addressed. 



.Most treatises on plant pathology deal with the more 

 extrinsic aspects of the matter, such as the host and the 

 parasite, and some of them give accounts of the evil 

 I results of an unfavourable environment. Bat in the book 

 before us the questions raised are discussed from a more 

 philosophical standpoint. The effort is made to discern 

 wherein disease itself really consists, and to ascertain the 

 actual relations and changes involved in the transition 

 from the healthy or normal to the abnormal and patho- 

 logical condition. "Disease (not diseases) in Plants" is 

 the title of the book, and it fully indicates the general 

 purport of the contents. 



In order to place the reader in a position to appreciate 

 the nature of the connection between a healthy and a 

 diseased state, the opening chapters are devoted to a 

 consideration of the normal physioloyy of the plant- 

 organs and their relations with their surroundings. Then 

 the various disturbing influences which make for, or 

 actually induce, disease are passed under review, and 

 their operations as far as possible explained. The im- 

 perceptible gradations by which an organism passes from 

 the healthy to an unhealthy condition are pointed out, 

 and the oftentimes indirect operation of an unfavourable 

 influence is insisted on. One is brought into closer 

 quarters with the heart of the matter on recoj^nising that 

 the most injurious factors are those which operate 

 through the metabolic processes of the plant ; just as, it 

 may be remarked, is malnutrition in the widest sense at 

 the bottom of so many of the ills which the animal flesh 

 assumes itself to have inherited. The interference may 

 come through unfavourable conditions of life, or it may 

 be more immediately traced to influences exerted by 

 other organisms such as parasites and the like. .-Vncl 

 these considerations open the way for discussing the 

 question of " predisposition " and examining the various 

 avenues in this direction leading to possible remedial 

 measures. 



Of course in a work of this kind there are some views put 

 forward which may not command universal acceptance, 

 but they are chiefly those concerned with side-issues, 

 and can hardly be profitably discussed within the limits 

 of a brief notice. Enough, it is hoped, has been said to 

 emphasise the fact that the book forms a valu.able con- 

 tribution to a subject of vast importance. For on the 

 right understanding of the nature and causes of disease 

 in plants hang many great commercial and even national 

 interests. The annual loss incurred through the agency 

 of disease is enormous, but the results of current work 

 clearly demonstrate ih.it much of this loss can be cur- 

 tailed or prevented when its causes are understood and 

 empirical remedies have given place to intelligent 

 counteraction. J. B. K. 



