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6 of the species of each genus, and references to the places where the species are described. This list is of great utility, inasmuch as the latest systematic account of British Fungi is dated in 1832, being comprised in the second part of the fifth volume of Sir E. Smith's "English Flora." Since 1832, vast numbers of species, new to this country, many of them also new to science, have been discovered and described; but the student in search of them was driven to a roving expedition through the successive volumes of the "Annals of Natural History," and of one or two other works, before these additional species could be ascertained. By the references given in Mr. Berkeley's book, taken in connexion with the explanation at page 305, which we think would have been better placed in the Preface, or in one of the early chapters, any species may now be readily referred to.

The book is divisible into two parts, viz., the introductory portion, consisting of 13 chapters, and the systematic arrangement. The former part contains a concise account of the different divisions of the whole tribe, as well as of the nature and habitats of Fungi in general, and their geographical distribution. This is followed by an account of their mode of growth, structure, and method of propagation, as well as of the variations of form which they assume. The uses of Fungi, and the diseases caused by them, are then described; and some remarks are added, showing what has been done with regard to their cultivation, and the manner in which they should be collected and preserved. The whole of this introductory matter is admirably adapted for guiding the student, who will give his energies to the subject, to an acquaintance with this most interesting branch of botanical science.

The work being professedly intended for popular use, any lengthened discussion of intricate mycological questions would have been out of place; but one or two such questions come to the surface here and there, upon which we have a few comments to offer.

In speaking of the genus Boletus, the author refers to the singular fact of the instantaneous change which takes place in the colour of the flesh, when broken, from white or yellow to dark blue; and he adds that this change, after being long a source of perplexity, is now known to depend upon the action of ozone upon the juices. Mr. Berkeley seems to adopt the opinion of M. Schoenbein, who examined the question in 1856, with reference to B. luridus. Schoenbein discovered a resinous matter like guaiacum, which, like that substance, turned blue when in contact with ozone. Since that time, it has been thought that Schoenbein' s investigations have not exhausted the subject; and the Belgian Academy lately proposed the following question for a prize essay:—"Determiner par des recherches a la fois anatomiques et chimiques, la cause des changements de couleur que subit la chair des bolets en general, et de plusieurs russules quand on la brise on qu' on la comprime." M. Kickz, one of the referees, in a report made to the