March 11, 189?. ] 



SCIENCE. 



357 



'background is not a plane as in the convex mir- 

 ror, but the surface of a sphere, and that the 

 proportion in which the images, as they ap- 

 ,proach the spherical surface contract, has a dif- 

 ferent mathematical expression." 



But in reality these differences are so funda- 

 mental as to make all the difference between 

 Euclidean and non-Euclidean ; for the changed 

 measure for distance in the mirror world is still 

 Euclidean, parabolic, using an imaginary conic 

 lin the plane background as ' absolute' in Cay- 

 ley's sense. 



Thus Helmholtz reproduced the old but 

 false theorem that in space of positive cur- 

 vature two geodetic lines, if they in general cut, 

 must necessarily cut in hvo points. He never 

 attained the conception of single elliptic space, 

 the type-form, but speaks only of ' spherical 

 space of three dimensions.' 



It is to be hoped that Professor Willson's 

 book may hasten the day in America when 

 -courses in descriptive geometry and pure pro- 

 jective geo^ietry, no longer confined to science 

 ■schools, may be available in every college, and 

 when there may be a naore adequate realization 

 ■of the power of spatial imaging as an instru- 

 ment in scientific research. 



Geoegb Bruce Halsted. 



Austin, Texas. 



• Chapters on the Natural History of the United 

 States. By R. W. Shufeldt, M. D., etc. 

 New York, Studer Bros. 1897. Pp. 480. 

 ■ This volume is a collection of articles, most of 

 which were published originally in ' Shooting 

 and Fishing' and other periodicals, and now 

 reappear, revised and somewhat expanded. A 

 wide range of topics is covered — insects, crus- 

 taceans, fishes, amphituans, reptiles, birds and 

 mammals occupy one or more chapters each, 

 by far the larger space being given to birds. 

 As a rule, each chapter treats some general sub- 

 ject, such as 'Crayfish and Crabs,' 'Gulls and 

 their Allies,' 'The American Warblers and 

 Sparrows,' passing the whole group in review, 

 mentioning some of its more striking forms, and 

 giving detailed descriptions of one or two spe- 

 cies, with extended accounts of their habits, 

 these latter often augmented by quotations of 

 •considerable length from various well-known 



authors. The anatomy of the animal under 

 consideration is occasionally touched upon and 

 questions of classification are frequently dis- 

 cussed — matters which, it may be feared, will 

 not prove very interesting to the general reader, 

 for whom the work is intended. 



The book is illustrated with a hundred and 

 thirty figures, many of them occupying full 

 pages. Nearly one-half are reproductions of 

 photographs of living animals, and are worthy 

 of considerable study for the light they throw 

 upon the possibilities and the difficulties in the 

 use of photography for zoological illustration. 



C. F. B. 



SOCIETIES AND ACADEMIES. 



BIOLOGICAL SOCIETY OF WASHINGTON, 287TH 

 MEETING, SATURDAY, FEBRUARY 26. 



Dr. E. a. De Sohwbinitz presented a paper 

 on ' The Treatment of some Animal Diseases 

 with Antitoxic Serums,' briefly reviewing the 

 work as carried on in the Bureau of Animal In- 

 dustry some years ago for the purpose of treat- 

 ing animals with the poisons formed by the 

 swine plague and cholera suis germs. This 

 work was fairly successful from an experimen- 

 tal standpoint, but did not seem to warrant 

 practical use in the field on account of many 

 difficulties which might arise. The preliminary 

 experiments made in the Biochemic Laboratory 

 with the serum of animals immune to cholera 

 suis, in 1892, and again with those immune to 

 cholera suis and swine plague germs, published 

 in August, 1896, showed that these two diseases 

 of swine which cause such enormous losses to 

 the farmers of the country could be cured in 

 experimental animals. Accordingly, practical 

 field experiments were tried, which demon- 

 strated that sick herds could be greatly bene- 

 fited and a large portion of the animals cured 

 if they were given injections of sufficiently 

 strong serum that had been carefully prepared 

 for the purpose of curing the two diseases above 

 mentioned. The expense of this method if le- 

 gitimately conducted is comparatively small, 

 and it is possible to prepare a serum that would 

 have the desired curative effect which should 

 not cost more than 10 cents for each injected 

 animal. Further practical experiments on a 

 more extensive scale will be conducted, but the 



