R E V I E W 8 . T m JOURNAL OP MICROSCOPY AND NATURAL SCIIIENCE, BEING TEE JOURNAL OF THE TIXIS journal, which will in future, me understand, be published quarterly by Messrs. BailliGre, Tindall and Cox, is an exceedingly interesting one. The Society was, we are informed, founded in 1873 to aid in the study, discussion, and circulation of microscopic objects, and to advance the pursuit of natural science among its members. It is divided into thirteen circuits of about twelve members each, arranged geographically. A box of slides, accompanied by MS. book for the insertion of notes and memoranda, is sent by the hon. secretary, at fortnightly intervals, to the first member on one of the circuits ; who, after keeping it for three days, must send it on by post to the next on the list, and he to the following one.When it has gone round the circuit, the last member returns it to the hon. secretary, who will then forward it to the &st member of the next circuit, and so on, until the slides have been seen by the whole of the Society. Each member ia expected to contribute six slides annually, which are returned to him after they have been round the circuits. Ladies, as well as gentlemen, may be elected members of the Society. As a rule, the journal, being conducted by the members, as it were, cow antore, is very readable, andnot only so, but exceedingly instructive and interesting to microscopists. ON THE HE-ILTIIY MANUFAOTURE OF BREAD. By Beqy'ami~ Vwd Richard8on, lcI.D.t F.R.8. London, Baillidre, Tindall and Cox. THIS is a well-written pampldet, designed to advance the taste of the public for apated bread manufactured upon Dr.Dauglish's system. There ia nothing particularly novel or atpiking in its composition, but the name of its authoi. will, doubtless, lend weight to it, and help to convince the public in favow of his views. Itt of coume, deals in a popular and easily comprehensible manner with the chemistry of fermentation. b m r A L CAkms. By Hew?/ sews%, XI?. C"8. ard s.D.8. Reprinted from the Jouraal ALTHOUGH not a strictly chemical work, this book is yet interesting to the chemist and microscopist, as the ituthor takes the view that carie8 of the teeth has a distbctly POSTAL MICROSCOPICAL SOCIETY. Edited by Alfred Men, 35012. Secretary. of the Byitish Dental Association, London, Bailbe, Tindall and Cox.-- ------- THE ANUYST.-_-_I_----- 210 --- chemical origin, being started frequently by a generally acid state of the saliva. These a d s , according to Mr. Bewill’s viers, are principally malic, butyric, and acetic, and are the products of chemical change and fermentation, set up in the fragments of organic matter-food, mucus, and epithelial scales-which are commonly present in the mouth, and lodged upon the teeth. Acid may be derived from several other sources. It may be secreted by the fl~zucous membrane. The normal secretion of the membrane is small in quantity, and slightly acid. I n health, the acid is at once neutralised by the alkaline stliva, with which it mingles; but when the membrane is congested or inflamed, t.he mucus increases in quantiw, and becomes more sfxongly acid in character.Then again, many forms of organisms themselves produce acid. Acid is eructated in many gastric disorders ; and an acid, instead of alkaline, reaction is shown by saliva in several as- eases. The whole work, dealing as it does with tho nzicroscopical and chemical characters of sound and decayed teeth, is evidently the product of much thought and research, and the arguments contained in it, are, in many places, exceedingly striking. The treatment recommended is not within our province to discuss, but generally qeaking it is alkaline (use being made of borax) and antiseptic. The author does not agree with the wholesale condemnation of the use of the tooth-pick we freqiiently see indulged in, but on tho contrary recommends its employment every night before going to bed, followed by a good rinsing of the mouth with the alkaline and antiseptic lotion, for keeping t.he teeth in good condition. It is a book that dl really enhance the author’s fame, both d t h his fellom professional men, and with the public who happen to come across it.