122 



NA TURE 



[June io, 1897 



much there is to be seen and learnt in the natural history 

 of the diseases of forest and field and garden plants, and 

 Tubeuf's examples should stimulate botanists to pay more 

 attention to the subject. It is true the reproductions of 

 the photographs are by means of the detestible " process 

 blocks," which disfigure most of the books of the present 

 age ; but I suppose we must agree that the choice lies 

 between these or none, as prices and means go. 



It will be evident that the book is too large for even a 

 brief review of more than the principal headings, but 

 there are one or two features of importance which stand 

 forth in salient contrast to anything met with in similar 

 works. 



These are signs of the times. One of the most striking 

 is the far too meagre note on " selection of hardy 

 varieties " — the word " hardy " does not accurately trans- 

 late the original. From all sides we are now hearing that 

 different varieties of vines, potatoes, wheat, &c., show 

 different disease-resisting powers, and Tubeuf says, 

 "An important method for the protection of plants 

 from disease . . . consists in the selection and cultiva- 

 tion of varieties and species of plants able to resist the 

 attacks of parasitic fungi." 



The very brief account of what has been done with 

 the vine, and the reference to what has been discovered 

 about wheat, will only leave the reader hungry for more 

 information. 



In Eriksson and Henning's exhaustive volume on 

 wheat-rust — to which I can discover no reference here, 

 the author confining his remarks to a note they published 

 last year in the Zeitschrift f. Pfianzenkrankheiten — 

 the student will find that as matter of fact some varieties 

 of wheat suffer little, and others much from Pucciniaj 

 and their extended investigations show that no mechanical 

 theory as yet proposed explains this., but that a complex 

 physiological phenomenon is here before us. They also 

 show that the Puccinia of wheat-rust also varies, both 

 morphologically and in its physiological relations to the 

 disease. We have, in short, to face the fact that the 

 culture of wheat-rust (for we do cultivate it), as well as 

 the culture of cereals, result in the variation of both 

 fungus and cereal, and it appears that selected varieties 

 of both arise and are propagated. 



Such varieties of parasitic fungi are also known in other 

 groups — e.g. Periderniium, Gymnosporangium, Usttlago, 

 &.C. — and Tubeuf gives a short note under the respective 

 heads ; and we have several indications that physiological 

 races are as common among parasitic fungi as they are 

 among bacteria. 



Clearly it is matter for experimental inquiry how far 

 these variations are independent or concomitant, and it 

 may be considered that one of the strongest reasons for 

 encouraging the carrying out of agricultural experiments 

 on a large scale, and the gathering of statistical results, 

 that scientific men can urge, is the hope that more light 

 will be thrown on the relations of these variations, and 

 that we may succeed in utilising the knowledge in the 

 practical evasion of disease. I remember being strongly 

 impressed, in 1 880-81, by the varietal differences between 

 the Hemileia on coffee and that on Canthium in Ceylon 

 and even then threw out the hint that the former had been 

 derived from the latter ; but the comparative immunity 

 oi Cqffea Liberica a.s contrasted with C. Arabica^ suggested 

 NO. 1 44 1, VOL. 56] 



that it was not impossible that a disease-resisting coffee 

 should be found. 



The subject is complex, and bristles with difficulties ; 

 but that is no reason for hesitating as to the experimental 

 inquiry ; and indeed it has already been commenced in 

 several countries, as the reports from Australia, America 

 and elsewhere show. 



Another feature of interest and importance in Von 

 Tubeuf s book, is the chapter on " preventive and com- 

 bative measures," involving the treatment of diseased 

 plants by means of chemicals. Here, again, I notice a 

 lack of attention to the English literature : Berkeley, and 

 others of our countrymen, had experimented with sulphur 

 in various forms, long before most of the authorities men- 

 tioned had taken the matter up. Still, it is quite true, 

 the introduction of Bordeaux-mixture, and its employ- 

 ment on the enormous scales adopted in France, Australia, 

 America and elsewhere, have taught us much, and sug- 

 gested more. It is a common mistake to suppose that 

 the intelligent application of remedial measures to plant- 

 diseases does not pay— there are plenty of witnesses to 

 the contrary ; but, unfortunately, school and university 

 courses generally have allowed of so little attention to 

 the knowledge that must be utilised in carrying out such 

 measures, that even skilled farmers, foresters, and other 

 cultivators of plants, have to enter upon these experiments 

 quite unequipped for carrying them out properly. 



Tubeuf s chapter on the "economic importance of 

 diseases of plants " may be cordially — if sadly — recom- 

 mended to all who are interested in the very necessary 

 extension of technical education by the institution of 

 agricultural schools and colleges. He quotes the losses 

 due to the Californian vine-disease (1892) at 10,000,000 

 dollars; in 1891 the wheat-rust cost Prussia over 

 20,000,000/., and Australia something like 2,500,000/. 

 Even allowing for large exaggerations— though reports 

 from Sweden, India, Ceylon, the West Indies, and else- 

 where suggest similarly large losses from fungus epi- 

 demics—in these estimates, it is evident that we have 

 here to deal with annual losses of which even a saving 

 of a very few pounds per cent, would be worth considera- 

 tion ; and the comparatively meagre experiments to hand 

 hold out hopes of much more considerable saving, if 

 steps are taken in time, with a due and intelligent know- 

 ledge of the problems to be faced, and the methods of 

 facing them. 



This must suffice for our review of this excellent book, 

 the technical details of which are well treated, of the 

 highest importance, and abounding with interest to the 

 naturalist and botanist, as well as to the technologist and 

 practical cultivator. H. Marshall Ward, 



CAPTAIN LYONS' REPORT ON THE ISLAND 



OF PHIL.i:. 

 A Report o?i the Island and Temples of Philce. By 



Captain H. G. Lyons, R.E. ; with an Introductory Note 



by W. E. Garstin, C.M.G. (Printed by order of H.E. 



Hussein Fakhri Pasha, Minister of Public Works in 



Egypt, 1897.) 



THE proposal to build a dam at Philte, which was 

 brought before the Egyptian Government a few 

 years ago, at the instance of Mr. Willcocks, of the Irri- 

 gation Department of Egypt, will be fresh in the memory 

 of many of our readers, even though the details of the 



