September 15, 19 10] 



NATURE 



327 



before us, the series should find high favour with the 

 gardening public. 



In " Niedere Pflanzen " and "Die Heide " we have 

 two small German natural history books; the former 

 deals with ferns, mosses, fungi, and algae, and is a 

 wonderfully compact and comprehensive little book, 

 copiously illustrated with a frontispiece of Equisetum 

 in colour. "Die Hiede " opens with an inferior 

 coloured plate of CuUuna, with attendant insects, but 

 the letterpress demands full praise and the illustra- 

 tions throughout the text are well executed. The 

 history of the heath lands, the component plants, &c., 

 are described in detail, and the biology of the flowers 

 is also fully dealt with ; a chapter is devoted to the 

 trees of the heath land. The latter portion of the 

 book gives an account of the animal life of the moor, 

 and numerous figures are given of the various insects 

 associated with this formation. Both volumes are 

 practical and useful works, and the latter especially 

 affords a model which might well be copied in Eng- 

 land. 



"Das Holz " is a short practical forestry manual, 

 which, in small compass, gives a mass of useful in- 

 formation as to forestry matters in general, such as 

 wood structure, measurement of timber, felling, haul- 

 age, &c., and of the industries connected with timber. 

 A book on these lines would probably find a ready 

 sale in England, and be of considerable value. 



"Der Pflanzengarten " is concerned with the design 

 and usefulness of a garden as a place for study, and 

 is principally occupied in giving a description of the 

 garden at the Kgl. Mariengymnasium, Posen, and 

 with an account of the plants found therein. 



OVR BOOK SHELF. 

 The Black Bear. By William H. Wright. Pp. vi + 

 12-. (London : T. Wenit-r Laurie, n.d.) Price bs. 

 net. 



In this well-illustrated volume the author has done 

 for Ursiis americanus that which he accomplished so 

 successfully for U. horribilis in its fellow (see Nature, 

 vol. 82, pp. 42,^-4, 19 10). The first fifty pages are de- 

 voted to a young black bear reared and tamed bv 

 Mr. Wright, while in the remainder the distribution 

 and habits of the species are discussed in a manner 

 indicative of intimate knowledge. Indeed, the author's 

 acquaintance with the black bear appears to be as 

 close as with its larger grey cousin. "Cinnamon" 

 bears, it is shown, may be either of the black or the 

 grey species, and the author is disposed to regard the 

 glacier-bear ( f '. cmiiuntsi) and the white bear of 

 Gribble Island ((_'. kcrmodei) as specifically insepar- 

 able from the former. From among a number of 

 interesting notes, attention may be specially directed 

 to the author's observations with regard to the ex- 

 treniely small size and imperfect development of new- 

 born bears, especially those of the present species. 

 The cubs of the black bear are at first "absurdly 

 small and pitifully helpless, weighing only from 8 to 

 iS ounces each, according to the number in the litter, 

 and are born about two months before the dam 

 emerges from her winter cjuarters." An old bear will 

 weigh about 400 lb. ; and the pups of a 40 lb. dog will 

 be as large as the cubs of a bear of this weight. To 

 explain this, the author suggests that a hibernating 



NO. 2133, VOL. 84] 



bear, which, of course, takes no food, could not nurse 

 cubs proportionately so large as those of the dog; 

 and, whether or no this be the right explanation, there 

 can be little doubt that there is some connection 

 between the hibernating habit and the diminutive size 

 of the cubs. 



The book is pleasant reading, and full of hunting 

 and forest lore. R. L. 



Chemistry for Pliotogralyhers. Hy Chas. F. Town- 

 send. Fifth edition, revised. Pp. 129. (London : 

 George Routledge and Sons, Ltd. ; Dawbarn and 

 Ward, Ltd., n.d.j. Price is. net. 



The more of chemistry and physics the photographer 

 knows the better is he able to understand his work, to 

 overcome difificulties, and to meet new contingencies. 

 It is impossible to set forth the main facts of chemistry 

 in so small a volume as this, even if the matter is 

 restricted to those subjects that have an immediate 

 bearing on photography ; but it is possible to do some- 

 thing useful in this direction even within so few pages. 

 The author commences with burettes and pipettes, and 

 goes on, rather unnecessarily, to gallipots and jampots. 

 \\'e do not think that such expressions as "The iron, 

 as it were, says to the silver, ' You've got my NO,; 

 drop it ! ' And the silver has to drop it," assist in 

 representing the subject clearly, and in this case the 

 description would appear to give an incorrect impres- 

 sion. From about the middle of the book the chem- 

 istry almost disappears in favour of practical and em- 

 pirical formula, with short instructions for various 

 photographic operations. Some of the author's state- 

 ments are open to criticism. We read, on p. 62, that 

 "all chemical reactions are reversible." That as, when 

 a photographic plate is exposed to light " there is no 

 outlet for the products of decomposition — the excess of 

 bromide or other halogen set free on reduction in this 

 case — a state of equilibrium is reached at a certain 

 point. If decomposition is carried beyond this point, 

 reversal sets in, which may go the whole way until 

 the original compounds are re-formed." At p. 86 we 

 read that carbon tissue is thin, and at p. 94, in the 

 five and a half lines devoted to Dr. Smith's " L^to " 

 paper, that " it is rendered colour sensitive by means 

 of anethol." Other misleading or unpractical state- 

 ments might be quoted. .\ photographer who wishes 

 to know something about combining proportions, the 

 general properties of acids and alkalies, and a few 

 other elementary chemical matters, will probably find 

 what he wants here, with a good many items of 

 miscellaneous information added. 



Die Aufzuchf uiid Kultur der Parasitiseheii Sawen- 

 pflanzen. By Prof. E. Heinricher. Pp. v + 53. 

 (jena : Gustav Fischer, 1910.) Price 2 marks. 

 Following upon his original investigations on 

 Lathrsea and other parasitic genera of the Scrophu- 

 lariacese. Prof. E. Heinricher has prepared this small 

 volume dealing with the propagation and cultivation 

 of parasitic seed-plants that will appeal especially to 

 gardeners charged with the supply of material for 

 botanical laboratories. The notes refer to well-known 

 European parasites and hemiparasites, and some less 

 common genera, such as Tozzia, Osyris, and Phelipaa. 

 One of the most interesting is Osyris alba, which 

 flourishes and produces fine suckers on willows. 

 Phelipaea^ biebersteinii, one of the Orobanchaceae in- 

 digenous to the Crimea and the Caucasus, is worth 

 growing for its flower: its natural host is Centaurea 

 dealbaia. .Another novelty recommended by the author 

 is a pot of Mclampvrum arveiise, which feeds on the 

 roots of several shrubs and small trees. 



