i893. SOME NEW BOOKS. 385 



agriculturist is that the interstices of the soil must be filled with air, 

 and not saturated with water like a sponge. 



Chapter II. deals with food obtained by the plant from soil, and 

 is excellent as far as it goes, the student being taught that soluble 

 substances only can pass into the roots, and that there are certain 

 substances in the soil, soluble in water, which are absorbed by the 

 roots for food, but no reference is made to the greatly increased 

 power of solution afforded by the acid reaction of the root-hairs, or 

 the carbonic acid gas dissolved in rain-water. 



The nature of the soil, the "substances of a leaf," the composi- 

 tion of the air, and the absorption of carbonaceous food therefrom, 

 are well explained, though surely in the heading on p. 40, "The 

 Seed obtains Food from the Air," we should read Seedling for Seed. 

 In the seventh and last chapter, on the source of the nitrogen 

 required by plants, the author is a little too crude and brief in his 

 explanation of nitrification and the tubercles on the roots of legu- 

 minous plants, " full of minute creatures, to which the name of 

 bacteria have (sic) been given." The two appendices " Notes on the 

 Experiments," and " On the use of the balance," contain useful hints. 



Mr. Laurie should have got a botanical friend to look over his 

 proofs, and thus have avoided the serious errors which mar what 

 might have been a capital little book. 



Precis de Teratologie, Anomalies et Monstruosites chez l'Homme et chez 

 LES Animaux. Par L. Guinard, Chef des Travaux de Physiologie a I'Ecole 

 veterinaire de Lyon. Precede d'une preface par M. le Dr. Camille Dareste. 

 Pp. 512. With 272 figures. Paris : J. B. Bailliere et Fils, 1893. Price 8 francs. 



After the great work of Is. Geoffroy-Saint-Hilaire, published from 

 1 832-1 837, for many years there was little done in Teratology. A few 

 isolated papers contained descriptions of unusual monsters, but the 

 attention of naturalists was so absorbed by the new light thrown on 

 the domain of normal Nature that her freaks and sports were almost 

 disregarded. Then, in quite recent years, came Camille Dareste's 

 series of studies on the artificial production of monsters, and a number 

 of other studies of which Mr. J. A. Thomson gave an interesting 

 resume in the last number of Natural Science.^ The more recent 

 part of the study of monsters concerns itself with the conditions of 

 their production, and has been called by Dareste Teratogeny, as dis- 

 tinguished from Teratology, the record and classification of the types. 

 The present volume is limited designedly to Teratology, and is 

 meant to be a compact and convenient guide to the known types of 

 abnormality ; for, if it be, at the first glance, a paradox to write of 

 types of abnormality, or to discuss the laws of disorder, a very brief 

 study of M. Guinard's volume will convince that monsters are not 

 the frolic of chance, but an inverted or tip-tilted regularity. Some 

 are caused by mere mechanical pressure or torsion, and cause and 

 effect tread on each other's heels as closely as the pressure of a booi 

 and the growth of a corn ; in others unusual condition, raising or 

 lowering the temperature beyond the eurythermal limits, alteration 

 of the natural position, conditions of strain (as on a centifrugal 

 machine) tend to produce abnormalities, although the nexus of cause 

 and effect is invisible ; but, however produced, the productions fall 

 readily into categories. M. Guinard gives, in a series of chapters, 

 accounts of simple anomalies, classified according to the organs or 



^ Natural Science, vol. ii., pp. 294-306. 



