520 



NA TURE 



[March 29. 1900 



although the wheat harvest of the world was much above the 

 average, was due to a severe and extensive rye famine in Russia, 

 and to the supply in two preceding years being inadequate to 

 meet the demand. 



From a lengthy " note " on the food supply of the United 

 Kingdom, Belgium, France and Germany, by Mr. R. F. 

 Crawford, published in the Journal of the Royal Statistical 

 Society, we learn that the average dietary of an inhabitant of 

 the United Kingdom contains a much larger quantity of meat 

 than that of a Belgian, Frenchman or German, but a smaller 

 proportion of bread and potatoes. In Belgium more bread and 

 less meat are consumed than in any of the other countries 

 named, while in France a noteworthy feature is the apparently 

 small consumption of milk. In the case of potatoes, the con- 

 sumption per head in Belgium and Germany is about three 

 times that in Great Britain, but the considerable requirements 

 are largely accounted for by their use in the manufacture of 

 starch and spirits. 



A FRESHWATER chert from Asia Minor is the text of Mr. W. 

 T. Haydon's presidential address to the Liverpool Microscopical 

 Society, published in the thirty-first annual report of the 

 society. The investigation was based on the examination of 

 some " worked flints" from Hermanjik imported in cargoes of 

 horse beans, which flints were doubtless used as teeth in thresh- 

 ing boards. Thin sections of the flints were remarkably rich in 

 organic remains, chiefly vegetable, including mosses, hepaticEC, 

 pine pollen grains, ferns and grasses ; while remains of mollusca, 

 diptera, spiders, &c., were also found. In endeavouring to 

 explain the origin of the silica forming this deposit, an examina- 

 tion was made of some chalk-rock from the same neighbourhood, 

 and this was found to contain great numbers of unmistakable 

 remains oi diatoms, but all traces of these disappeared in hydro- 

 chloric acid. Mr. Haydon's conclusion is that the flint deposits 

 derived their silica from the diatoms, and that the forms of the 

 latter, as represented in the calcareous rocks, were " pseudo- 

 morphs " whose silica was replaced by calcite. 



A NOTE on the use of formalin as a preventive of silkworm 

 disease is given by Prof. G. Gianoli and Dr. E. Zappa in the 

 Rendiconti del R. Istituto Lombardo (xxxiii. 2, 3). From 

 experiments, it appears that the diff"usion of formic aldehyde in 

 the form of vapour through the breeding chambers containing 

 the silkworms is not a certain preventive of Botrytis bassiana, 

 a fact which the authors attribute in some degree to its high 

 chemical activity, which causes it to be absorbed by various 

 objects, such as the leaves on which the silkworms feed. On 

 the other hand, the presence of this vapour produces a diminu- 

 tion in the weight of the cocoons, and a deterioration in the 

 quality of the silk. 



In the March number of the Zoologist Mr. J. H. Gurney gives 

 a plate of one of the so-called " Chestnut Partridges " which have 

 recently excited so much interest in Norfolk. It is stated that 

 .a local race of these abnormally coloured birds has now been 

 established; the figured specimen being the twelfth example. — 

 The same number contains the conclusion of Mr. Distant's 

 article on " Mimicry," to which allusion has been previously 

 made in these columns. "The theory of mimicry," writes the 

 author in his concluding paragraph, "is probably the still 

 imperfect recognition of a great truth which is struggling to 

 survive a mass of more or less irrelevant evidence too frequently 

 offered in its support. . . . Whatever view be held, this alone 

 is certain, that the theory in either its demonstrated or sugges- 

 tive enunciation has been the means of a vast record of facts 

 pertaining to the life-histories of animals and plants which would 

 otherwise have remained either unobserved or disregarded." 

 Can more be demanded in favour of any working hypothesis ? 

 NO. 1587, VOL. 6l] 



Miss Eleanor Ormerod's Twenty-third Report on In- 

 jurious Insects and Common Farm-Pests has just been issued. 

 From this it appears that during 1899, in addition to the 

 ordinary insect infestations, there occurred developments of 

 species which had hitherto been but little noticed. None of 

 the infestations were of a very serious nature, with the exception 

 of the so-called Turnip-Fly, which was very prevalent in some 

 parts of the country. A feature of the year was the marked 

 absence of injury to root-crops by visitations of Caterpillars and 

 Mangold-leaf Fly ; while orchard-haunting Caterpillars, as well 

 as those of the Gooseberry, and Currant Moth, were likewise 

 conspicuous by their absence. Hessian Fly was recorded from 

 one district; and in this connection the author draws the 

 attention of farmers to the extreme importance of destroying 

 wheat-screenings containing the pupae of this noxious insect, 

 in the form of the so-called "flax-seeds." A section of the 

 Report is devoted to the Grouse-Fly, which appears to be more 

 interesting to the entomologist than harmful to the prospects of 

 the sportsman, as there is no evidence that it does any 

 appreciable injury to the birds it infests. The remarkable 

 structure of the foot of this insect is illustrated by a tinted 

 plate. 



.A Bulletin of the U.S. Department of Agriculture, by Dr. 

 L. O. Howard, on " Some Results of the Work of the Division 

 of Entomology," bears testimony to the attention bestowed on 

 the mitigation of insect ravages to crops and trees on the other 

 side of the Atlantic. A large portion of this Bulletin is devoted 

 to the life-history of two scale-insects of the genus Pulvinaria, 

 which infest maples, and occasionally do much harm to these 

 valuable shade-trees in various parts of the Eastern United 

 States. The second article treats of the insects which (together 

 with the newspapers, as it is significantly remarked) were re- 

 sponsible for the so-called ''kissing-bug scare" of the past 

 summer ; the account being published mainly to satisfy a shoal 

 of inquirers as to the truth of the newspaper stories. Reports 

 on the devastation caused by locusts in tlie Western Territories 

 during 1899 are of especial interest at the present time on 

 account of the recent arrival of flights of the true Rocky Moun- 

 tain Locust {Melanoplus spretus) in certain districts of the North- 

 west. Housekeepers in many parts of the world will be 

 interested to hear of a simple Australian remedy for cock- 

 roaches, consisting of a mixture of flour and plaster of Paris, 

 which is greedily eaten by the insects and rapidly sets in their 

 stomachs. 



Yet another serial dealing, in part, with insect pests is to 

 hand, in the form of the February number of the Agricultural 

 Gazette of New South Wales. The contents of this number are 

 varied and interesting, ranging from such subjects as the proper 

 mode of stretching barbed wire and the pruning of plants, 

 to the incubation of eggs and the bacteria found in milk and 

 butter. It is undoubtedly a healthy sign when it is considered 

 advisable to teach poultry-raisers the changes which take place 

 in eggs during incubation ; and the excellent figures with which 

 these changes are illustrated, as also those displaying milk and 

 butter bacteria, are worthy of the highest commendation. 



M. E. Laurent has an interesting note, in the Bulletin of 

 the Royal Botanical Society of Belgium, on the distribution of 

 the mistletoe in that country. While almost entirely absent 

 from Holland, its distribution in Belgium is local, and appears 

 to have some connection with the nature of the soil, preferring 

 that of a calcareous character. The trees on which it either 

 grows naturally, or has been artificially inoculated, are Salix 

 vifTiinalis and grandiflora ( ? ), the fig, the olive, Eucalyptus 

 globulus, the oleander, the hawthorn, the apple, the pear, the 

 medlar, the quince, and Malus spectabilis. On Ficiis elastica, 

 Spartium iunceum, and some varieties of the pear, the berries 



