May 30, 1889] 



NATURE 



99 



been elaborated by Willkomm and Lange — by foreigners 

 again, and not by Spaniards ! As a noteworthy exception 

 to the botanical lethargy of the Spaniards, the learned 

 and valuable works on the botany and botanists of the 

 Iberian Peninsula by Don Miguel Colnieiro deserve spe- 

 cial mention in this connection. Boissier himself, although 

 he soon afterwards became engaged upon a work of much 

 greater magnitude, never lost interest in the flora of 

 Spain, and he revisited the country many times. Even 

 before the completion of his " Voyage en Espagne," he 

 commenced travelling and collecting in South-Easlern 

 Europe, subsequently visiting Egypt, Palestine, and 

 Arabia, and other countries ; the results of these journeys 

 culminating in his magnum opus, the " Flora Orientalis." 

 Preliminary to this work he published a vast number of 

 new species in fascicles, from time to time, between 1842 

 and 1859, under the title of " Diagnoses Plantarum 

 Orientalium Novarum." Another important contribution 

 to systematic botany was his " Icones Euphorbiarum," 

 a large quarto, containing figures and descriptive letter- 

 press of 120 species of Euphorbia. This was published 

 in 1866, and in the same year the author furnished de- 

 scriptions of the seven hundred species of this genus for 

 De Candolle's " Prodromus." 



Apart from its size, the " Flora Orientalis" is incontest- 

 ably one of the most masterly pieces of descriptive 

 botany ever executed, and although many botanists will 

 not agree with the illustrious author in his limitation of 

 species, all will recognize the excellence of the de- 

 scriptions, and admit that by their aid a botanist can 

 actually " determine " his plants. On this point I can 

 speak from successful personal experience. The analy- 

 tical keys to the species of some of the larger genera are 

 admirably constructed, and display a marvellously acute 

 knowledge, as well as great power of discrimination 

 Take such genera as CatnpaJiula (125 species), Cousinia 

 (136 species), Centaurea (183 species), Silene (204 spe- 

 cies), and Astragalus (757 spiecies), as examples of the work, 

 and it will be admitted that few approach it in quality. 



With regard to his conception of species, Boissier 

 rejected the Darwinian theory altogether, believing that 

 species were not arbitrary congeries of individuals, but 

 direct creations of God at different periods. And al- 

 though he by no means carried subdivision to the absurd 

 extent that some modern botanists have done, yet he went 

 much farther in this direction than most authors who have 

 dealt with the vegetation of so wide an area as that of the 

 ■" Flora Orientalis." 



The supplement, issued towards the end of last year, is 

 brought down to a very recent date, and contains all Dr. 

 Aitchison's additions to the Afghan flora, except those in 

 his last paper, of course, which was not published till 

 the spring of last year. It also includes an index to all 

 the collectors' numbers cited throughout the work, which 

 will be very useful to persons possessing these numbered 

 collections. A portrait of the author late in life forms 

 the frontispiece to this volume, and there are several 

 views of the new building erected on the bank of the 

 lake, not far from Geneva, to contain the fine herbarium 

 amassed by Boissier. 



Thus Geneva now possesses the remarkably rich 

 herbaria of De Candolle, De Lessert, and Boissier. 



W. BOTTING HeMSLEY. 



A TREATISE ON MANURES. 



A Treatise on Manures. By A. B. Griffiths, Ph.D. 

 (London: Whittaker and Co., 1889.) 



IN this substantial little volume of nearly 400 pages 

 the author treats of natural and artificial fertilizers, 

 with a decided leaning towards the latter. The work is 

 intended to be useful to manure manufacturers as well as 

 to farmers and students of agriculture, and must be 

 regarded as a useful addition to our information. The 

 subject is introduced by two chapters upon the soil and 

 the plant, after which all the leading and the suggested , 

 fertilizers are reviewed, and analyses are furnished. It is 

 convenient to have at hand a book written up to date in 

 which the newest sources of phosphatic materials, guanos 

 and alkalies, are brought under notice. The chief interest 

 of Dr. Griffiths's book centres in his chapter upon the 

 use of iron sulphate as a manure. It is well known that 

 Dr. Grifliths first pointed out that the iron sulphate, used 

 in small quantities of about half a hundredweight per 

 acre, exerts a beneficial effect on many crops ; and this fact 

 is distinctly brought before the reader in the book before 

 us. The value of sulphate of iron lies in the fact that 

 many soils do not contain a sufficiency of iron in a form 

 to be readily taken up by plants, and Dr. Griffiths con- 

 siders that when added to such soils it tends to increase 

 the amount of chlorophyll in the leaf, and that this is 

 followed by increased vigour in the elaboration of starch, 

 woody fibre, fats, carboliydrates, and albuminoids. The 

 amounts of increase of crop in the cases cited are re- 

 markable, and the greater percentage of iron in the ashes 

 of plants top-dressed with this substance is decided. It 

 would be unjust to Dr. Griffiths to detract from the value 

 of this observation, which, as he tells us, has been the 

 cause of hundreds of letters on the subject from all parts 

 of the world. The results are indeed open to the criticism 

 that they are almost too satisfactory, for an increase of 

 19,313 pounds per acre of mangel owing to the use of half a 

 hundredweight of sulphate of iron seems almost too good 

 to be true. Nine tons of mangel are worth something like 

 £(i sterling to the farmer as food for stock, a sum which 

 would effectually turn an unprofitable into a profitable 

 crop. The season is still young, and it would be well if 

 agriculturists would put Dr. Griffiths's results to the test 

 of a simple experiment during the coming summer, upon 

 root crops. 



Dr. Griffiths is no great partisan of farmyard manure, 

 and he is scarcely fair in his argument when he touches 

 upon this important subject. We cannot agree with him 

 that farmyard manure is "far from being a perfect 

 manure," or that " the farmer who uses nothing but farm- 

 yard manure exhausts his land," or that " farmyard 

 manure does not return to the soil all the nitrogen which 

 was originally extracted from it by growing crops." In 

 pursuing this argument he asks, " Whence comes the 

 fertilizing matter contained in the dung of animals.'' An 

 ox or a sheep cannot create nitrogen, phosphorus, or 

 potash. All of these substances, which are to be found 

 in its liquid and solid excrements, have been derived from 

 its food. That food has been grown upon the farm." 



This is doubtless true if the farm actually does pro- 

 duce all the food of the animals it supports ; but every 

 farmer knows that this is not the case. The believers in 



