278 



SCIENCE 



[N. S. Vol. XL. No. 1025 



growth, development, physiology of respiration 

 and digestion, his excellent summary of the 

 principal investigations on the determination 

 of age by means of the ootoliths, scales, oper- 

 cular bones and vertebrae, and lastly, in a few 

 pages relating directly to fish culture. 



A summary of the important literature is 

 given under each heading, emphasis being laid 

 quite naturally upon European publications. 

 This feature together with a full bibliography 

 will be especially helpful to American stu- 

 dents. The consideration of all recent ex- 

 perimentation and the judicious application 

 of the principles set forth is a most commend- 

 able characteristic of the whole work. 



G. C. Embody 

 The Care of Home Aquaria. By Eaymond C. 



OSBURN. 



This contribution of Professor Osburn's, 

 published by the New York Zoological So- 

 ciety as a volume of the New York Aquarium 

 Nature Series, on account of its small size 

 and necessarily popular character, is too likely 

 to be overlooked. The investigator of any 

 form of aquatic life will find aquaria of the ut- 

 most service, and will do well to refer to this 

 simple presentation of the fundamental prin- 

 ciples which govern their care. Under the cap- 

 tions The Meaning of Balance, Temperature, 

 Placing and Cleaning the Aquarium, Animals 

 that Will Live Well Together, Feeding, Ma- 

 rine Aquaria, The Care of Young Fishes, etc., 

 a great deal of broad, practical information 

 will be found arranged. Ample illustrations 

 are attractive rather than instructive. A 

 short appended bibliography will be found 

 useful. 



The following paragraphs are quoted more 

 or less at random: 



" The fact that animals require oxygen in 

 respiration and that green plants give oS 

 oxygen in excess were discovered and pub- 

 lished as early as 1Y78, but lovers of aquatic 

 life were slow to apply this knowledge. In 

 fact, it was not until 1850 that the first prop- 

 erly balanced aquarium was described by Mr. 

 Eobert Warrington of Manchester, England." 



" To supplement the surface absorption of 



oxygen, it is necessary to grow plants in the 

 aquarium." 



" It is a common but very mistaken notion 

 that an animal should have food at hand at 

 all times to keep it in good condition. It is 

 well known that various forms of domestic 

 animals, as well as the wild species confined 

 in zoological gardens, make the best growth 

 and keep in the most satisfactory condition 

 when supplied only with what food they will 

 clean up at one feeding. This applies with 

 equal force to the inhabitants of the aquarium, 

 but besides there is a real and grave danger 

 of contaminating the water hy supplying more 

 food than will he readily consumed." 



Emphasis is placed on the great educational 

 value of aquaria. The ordinary balanced 

 aquarium is a little world apart, in which 

 plants, fishes and microorganisms are mu- 

 tually interdependent, and the art of aqua- 

 rium-culture is to understand and control this 

 balance. 



John Treadwell Nichols 



Animal Flight, A Record of Ohservation. By 



E. H. Hankin. London, Hiffe and Sons, 



Ltd. 8vo. Pp. 413, 97 figures. 



Considering the many explanations we have 

 had of soaring flight, it is somewhat surprising 

 that we know so little about it and that stiU 

 further explanations seem necessary. The au- 

 thor of the book under consideration takes 

 care to state in the preface that " the present 

 book will be found to contain the facts in the 

 case, with no explanation at all," a statement 

 that seems at once/to claim too much and too 

 little. 



Until he has watched and recorded the 

 frigate bird and the albatross a large portion 

 of the facts must be considered as lacking, 

 while running through the record of the au- 

 thor's observations is an evident, though un- 

 expressed, belief that some oacult influence is 

 at the bottom of it all. 



The observations, for the most part, were 

 made at Agra, India, and the majority of them 

 on the kite, or eheel, Milvus govinda, though 

 they include the adjutant and three species of 

 vulture, all experts in soaring. 



