274 NATURAL SCIENCE. April. 



A Real Naturalist. 



The Natural History of Aquatic Insects. By Professor L. C. Miall, F.R.S., 

 with illustrations by A. R. Hammond, F.L.S. Pp. xii., 395. London: 

 Macmillan & Co., Ltd., 1895. Price 63. 



In the waste of books dealing with popular natural history, and 

 especially with entomology, Professor Miall's volume is the greenest 

 oasis. In one of the early pages he made us his friend for ever by 

 dissuading the young naturalist from collecting or trying to become a 

 systematist. "The man," says Professor Miall, "who can name 

 many insects can seldom do anything but name them (there are some 

 conspicuous exceptions ! )." Of course Professor Miall, like every other 

 scientific man, knows the retort that the systematist will make. The 

 systematist, like the bibliographer, is necessary, and there are faculties 

 that may be trained by the pursuit of either industry. But the faculties 

 trained by schoolboy collectors are as readily trained by the collecting 

 of stamps or buttons, and the collector soon comes to see in his bird 

 or beetle no more than a new specimen, in his case to be prized for its 

 rarity rather than for his knowledge of it. Under Professor Miall's 

 guidance, the schoolboy or other budding naturalist will be led to a 

 pursuit that will train his highest faculties, that will not aid the whole- 

 sale extinction of all the rarer creatures, and in which success cannot 

 possibly be accomplished by money. 



Professor Miall begins with a general introduction, in which he 

 discusses water as a sphere of life. He supports the view that aquatic 

 insects have taken to the water secondarily. In this he disagrees with 

 the ingenious theory due, if we remember rightly, to Sir John Lubbock, 

 that insects were primitively aquatic, the wings being modifications 

 of tracheal gills. Many of the most generalised insects are terrestrial 

 and aerial, while tracheae, which are found alike in land and in aquatic 

 forms, would seem to be typically structures of air-breathing terrestrial 

 creatures. Many of the peculiar features described by Professor Miall 

 are most easily explained as adaptations of the tracheae of terrestrial 

 creatures to aquatic conditions. The author in his introduction, and 

 repeatedly in his book, discusses those curious properties of the surface- 

 film to which he was the first to call attention. The use of the word 

 " film," and still more the relations of the film to the creatures living 

 upon it or under it, suggest that a layer of different tenacity, and 

 perhaps of different composition, forms on the surface ; but the author 

 is careful to state that the film is merely a physical condition of the 

 surface of a liquid in contact with air. He shows how most aquatic 

 creatures live either on the upper surface of the film, never really 

 being wetted, or on the under surface not coming in contact with air. 

 The various devices used to take advantage of the resistance of the 

 film, and to break it by force when necessary, are explained in the 

 most interesting and careful way. The greater part of the book deals 

 with the aquatic representatives of the different orders, beginning 

 with beetles and ending with bugs and spring-tails. From these 

 chapters we could quote suggestive and interesting novelties almost 

 without limit, but we prefer to advise our readers to turn to the volume 

 itself. 



Plants of Reunion. 



Flore de l'Ile de la Reunion, avec l'indication des proprietes economiques 

 ET INDUSTRIELLES DES PLANTES. Par E. Jacob de Cordemoy. 8vo. 

 Pp. xxvii., 574. Paris : Klincksieck, 1895. 



The little island of Reunion or Bourbon, situated to the S.W. of 

 Mauritius, has furnished Mr. Cordemoy with material for a good- 



