November 8, 1894J 



NATURE 



20 



humus, and otherwise ass!Stin<j in the nutrition of plants, 

 has yet to be dealt with in a special treatise. Considering 

 the exhaustive and expensive investigations which are 

 carried out in the research of animal pathology, a large ex- 

 penditure by the State on the influence of bacteria 

 on soil and water would be justifiable, and would lead 

 to highly important improvements in agriculture and 

 gardening. 



The editor meets possible objections from botanical 

 critics to Hartig's classification of fungi, by re- 

 marking that it is not fungi which are being studied 

 here, but their action on trees, and that students may 

 obtain a thorough knowledge of fungi elsewhere ; he 

 refers the forester who may be anxious to know the 

 remedies against disease to special works,' although 

 Hartig has given many practical hints as to treatment m 

 certain cases. 



The book's great value lies in the way it teaches 

 students how to investigate disease, and a wide field is 

 still open to discovery in this respect. 



The author's introduction chiefly deals with the causes 

 of disease and the procedure for investigating them ; and 

 it is reassuring to read that the transmission by inherit- 

 ance of disease is unknown in the vegetable kingdom, 

 and that we may use without hesitation the seed of plants 

 suffermg from any conceivable disease, and that with 

 them the law of inheritance is only involved in the case 

 of marked peculiarities, such as twisted fibre, dwarfed 

 habit, and other undesirable peculiarities. Superior 

 individual growth, however, is recognisable in the size 

 of the fruit, and large acorns produce vigorous oak 

 saplings. 



As regards the distribution of matter in the work, the 

 first forty pages after the introduction deal with diseases 

 caused by plants other than fungi. Hartig states that he 

 has not noticed any appreciable damage done to forest 

 plants by Cuscutea or dodders, but Hess states that osier 

 willows are greatly damaged by Cuscuta Cronovii, Willd., 

 an American species which has established itself in 

 Germany. The places where the haustoria, or sucker- 

 like roots of the parasite, pierce the cortex of the plants, 

 are rendered brittle, and the osiers so attacked become 

 useless for basket-making. The only remedy appears to 

 be to cut down the affected shoots in June and July, when 

 the dodder blossoms, and burn them. Bacteria which 

 cause such terrible diseases in animals rarely harm plants, 

 owing to the closed nature of their tissue elements as 

 compared with the anastomosing veins and lengthy 

 digestive apparatus of animals. 



The main portion of the book — pages 40-224— deals 

 with damage done by fungi ; and alter a general description 

 of their mode of life, a very clear account is given of the 

 life-history of each destructive fungus, and of its effects 

 on its host. Fortunately, whilst several of these species 

 may destroy a few hundred trees here and there, the only 

 fungus which can be compared for its ravages on whole 

 woods with certain destructive forest insects is Pcziza 

 Wilikojiunii, which causes the widespread larch disease, 

 and has rendered the cultivation of larch almost im- 

 possible in certain districts in Great Britain and the north 

 of Germany, though it is said not yet to have occurred in 



^ For instance, a translation of Hess» "Forest Protectioa " is tiow in 

 the press, and deals with these questions in detail. 



NO. 1306, VOL. 5 l] 



Ireland. The best preventive measure is to plant larch 

 only on suitable soils and in open airy situations, and to 

 mix it with other trees, and especially with beech. 



Besides dealing with fungi which infest living trees, 

 there is a most interesting account of those which attack 

 timber, and thoroughly practical suggestions are given 

 for dealing with dry-rot caused by Mcrulius lacrimans. 



Section ii. (pages 226-269) deals with wounds, and the 

 mode nature adopts for healing them, and also with the 

 dangers they aftbrd by the admission of the spores of 

 fungi to the interior of a tree. It is pointed out how 

 branches should be pruned or shortened so as to avoid, as 

 much as possible, the chances of future decay. Hartig 

 states that he has never known an instance of coal-tar, 

 when used for dressing wounds in trees, having proved 

 hurtful to them, although some foresters have asserted 

 the contrary. 



Section iii. (pages 270-281) deals with diseases due to 

 certain conditions of soil, the chief predisposing factor 

 being the want of free circulation'of air in the soil, which 

 may cause root-rot in conifers, though, according to 

 Hartig, never in broad-leaved species. This latter state- 

 ment may rot, however, be quite correct, as Spanish 

 chestnut appears sometimes to suffer from root-rot, owing 

 to this cause. 



Section iv. (pages 281-304) deals with diseases caused 

 by atmospheric influences, frost, insolation, want of 

 hght, hail, fire, coal-smoke, and lightning, and the book 

 terminates with a classified list of diseases arranged 

 according to the species of tree attacked, and the 

 respective organs which suffer. 



\V. R. Fisher. 



OUR BOOK SHELF. 



Le Centre de VAfriquc. Autour du Tchad. Par P. 

 Brunache. (Paris ; Felix Alcan, 1S94.) 



This record of travel in a previously unknown region 

 of north tropical Africa is published as volume 79 of 

 Bibliotlicqiie Scietitifique Internationale, although there 

 is nothing scientific about it, and the standpoint of the 

 author, so far from being international, is exclusively 

 and almost obtrusively French. The words " Autour du 

 Tchad," which are repeated as the running title of the 

 book, are entirely misleading, for the writer never came 

 into the vicinity of Lake Chad at all, but passed more 

 than 200 miles to the south of it. These are all the 

 adverse criticisms we have to offer. For the rest, the 

 book IS lively reading, and has the merits of brevity and 

 point. M. Brunache went out in 1891, as second in 

 command to M. Dybowski, in an expedition for the relief 

 of M. Paul Crampel, who had set out a year before, with 

 small resources, from French Congo, to try to reach Lake 

 Chad. Landing at Loango, the Dybowski expedition 

 went to Brazzaville, on the Congo, and thence up the 

 Mobangi and through a blank area of the map, peopled 

 by Dakoas and N'Gapus, across the watershed between 

 the Congo and Shari systems to neatly 8' N. The place 

 of Crampel's inurder was found, and a good deal of 

 punitive fighting was earned on with the IMohammcdan 

 negroes ; but here, at Crampel Peak, Dybowski found 

 that it was impossible to go farther, and the expedition 

 returned to the French outposts on the Mobangi. M. 

 Brunache is careful to show how much better qualified he 

 was for the command than the appointed leader, of 

 whose wishes he seems not to have been too considerate. 

 On his way to the coast our author met the expedition of 



