Page:Science vol. 5.djvu/543

 JUire 19. 1885.1

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��not necessary ; nnd ,vct. with this book in hand, the beginner may feel sure of not going astray, If be follows the (lireciioDa laid down iu it.

The book opens with a brief etatenieut of the various classes of bacteria, whjcli is followed b}' a consideration of the theory of spontane- ous generation, and the principles uptm which eteritization depends. Tliese latter are very well and briedy stoted. The various methods of sterilization are spoken of and explained. and due prominence is given to the method of ' discontinuous ' or ' intennitteut ' sterilization so much used at present.

The second chapter is devoted to the various rorins of bacteria, and to an elucidation of the microscopic technique. The method of obser- vation of unstained and staiued bacteria is fully shown, and the general principles of the aniline colors are explained. Ilere are brought together, in a convenient form, all the various staining-fliiids of Koch. Elirlieh, etc., with their formulae. The various accessories in the way of reagents and instruments, are, of coarse, included.

The importance of the bacillus of tubercu- losis in furnishiog a conclusive method for the di^nosis of this disease leads the author to devote a number of pages to the methods of staining this organism ; and all workers in this branch of iniestigation will be glad to find the run account of the methods of staining sporea which is given. The mclhoil of treating sections of the tissues for purposes of showing bacteria contained in them closes this portion of the work. The various culture methods and materials are clearly given ; and the for- mulae for the various nutritive media, are, of course, added. The advantages of the solid over the fluid cultures are so manifest as to need but a very few words ; but these advan- tages are here so clearly set forth, that any sceptic may be convinced if lie will but read the evidence.

Something is said cf llie saprophytic and parasitic liactcria, and a summary of the gen- eral biolt^cal problems involved is given.

The book closes with a few words on the special investigation of earth, air, and water.

All the more important implements needed are figured in very good woodcuts, and there are two litliographic plates showing various culture colonics and stained bacteria.

The work is a good one, and well done. It is especially needed at the present time of in- terest in all that belongs to bacteriological research, and will certainly prove useftil to any one interested in the subject who is able to translate easy German.

��Fossil algae are proverbially difllcult aud unsatisfactory subjects for study. Usually ol irregular aud variable forms, without definite and characteristic surface-markings, and com- posed only of cellular tissue which has entirely disappeared, they have left sliadowy outlines, or mere casts, that atford only the most gen- eral and superficial characters for compari- son among themselves or with living plants : hence there must be considerable uncertainty in regard to the botanical relations of even those best preserved ; while those which are more obscure are liable to be. and have been, confounded with tracings made by fioating objects, the tracks or burrows of ahnelids, with sponges, alcyonarians. medusae, and other soft-bodied and perishable organisms. Yet the supposed remains of seaweeds are so abundant in rocks of all ages, fi-om the Cambrian up. that they could not be ignored : and a large number of more or less distinct imprints, some of which are unmistaka- ble algae, have been figured and described by .Sternberg, Brongniart, and other writers on fossil botany who have followed them. Count Saporta is one of the latest and most learned of these writers, and one who has done much excellent work in his studies of the mesozoic and tertiary plants of France. In his vjiluable and voluminous contributions to the ' Palaeon- tologie Fran^aise,' and in his * L'^volution du r^gne v^gi^tal,' he has given a large number of figures and descriptions of what he supposed to be fossil seaweeds, and has attempted a more thorough review of this department of fossil botany than any one else has ventured on. As to the character of much of his material, there can be no reasonable doubt : but some of his specimens are too obscure to warrant any very i>oaitive assertions, and in some coses his conclusions have been questioned.

A somewhat sweeping criticism of ^iaporta's work was recently made liy Mr. A. G. Na- thorst (Bull, de la sac. gial. de France, ii air. t. xi. p. 452), who considers that most of his so-cnlled algae are simply casts of tracks or other impressions mechanically made on the se.i- bottom.

The work now published is largely a defence of the views heretofore held by Saporta, and it contains figures and descriptions of a number of the casts and impressions which have been the subjects of controversy. Among other things noticed are those peculiar and enigmat-

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