I 12 



NATURE 



[July 21, 1923 



should be of outstanding interest to students of 

 plant pathology and ultimately perhaps of very 

 great importance to agriculture. As a result of the 

 papers communicated at this meeting, it appears 

 that several cases of leaf mosaic and even that 

 important economic disease problem, the leaf roll 

 of potato, may have to be removed from the category 

 of virus diseases and assigned to the category of 

 diseases of which the causal agents are protozoa. 

 Ray Nelson is reported to have produced photo- 

 micrographs illustrating definite flagellate protozoa 

 found constantly associated with leaf roll of 

 potato and the mosaic of bean, clover, and tomato. 

 In the light of this paper, the tendency seems to 

 be to regard the intracellular bodies reported by 

 L. O. Kunkel, and by H. H. McKinney, Sophia H. 

 Eckerson, and R, W. Webb, in cases of mosaic 

 disease, as also protozoal in nature. It will be 

 remembered that Kenneth H. Smith briefly reported 

 in Nature of November i8, 1922, p. 668, the presence 

 of curious intracellular bodies in the case of mosaic 

 of potato, and demonstrated these at the meeting 

 of the Association of Economic Biologists devoted 

 to a discussion of virus diseases. A joint discussion 

 upon this subject between the Sections of Botany 

 and Agriculture is put down for the Liverpool 

 meeting of the British Association, and it is much 

 to be hoped that upon this occasion something may 

 be heard of this new work upon the subject, as the 

 report in Phytopathology concludes with the statement 

 that "without doubt this symposium marks an im- 

 portant milestone in the progress of plant pathology." 



Japanese Uromyces. — Seiya Ito, professor of 

 phytopathology. College of Agriculture, Hokkaido 

 Imperial University, has contributed a monograph 

 on the Uromyces of Japan, which forms Pt. 4, vol. 

 xi., of the Journal of the College. He describes 

 fifty-six species of Uromyces and three of Pileolaria, 

 giving figures of the spores ; ig species are endemic, 

 23 common to Europe, and 23 to America. One 

 new species is described, Uromyces Vicics-unijuga 

 Ito. Eight of these species had not previously been 

 recorded from Japan. Japanese rust fungi will in 

 future be known to us mainly through the investiga- 

 tions of Japanese mycologists, and yet it was only 

 in 1858 that M. J. Berkeley and M. A. Curtis described 

 the first two rust fungi recorded from Japan. 



Size and Form in the Vascular Tracts of 

 Primitive Plants. — Continuing his studies of the 

 influence of size upon form. Prof. F. O. Bower, in 

 the Proceedings of the Royal Society of Edinburgh, 

 vol. 43, Part I, concludes, mainly as the result of a 

 reconsideration of the figures of the axial stele and 

 petiolar trace in the fossil Ccenopterideae, that 

 increase in size is followed by decentralisation of the 

 vascular tracts. Various factors, such as mechanical 

 necessities, requirements of tissue ventilation, and 

 so on, may co-operate in bringing about this result, 

 but the author concludes that " there is certainly 

 some other factor which it is more difficult to define 

 than it is to point out its consequences." In the 

 light of the considerations now advanced Prof. 

 Bower is prepared to see a " writing down " of the 

 value of primary vascular characters for the purposes 

 of comparison and phylesis, as such characters may 

 result from homoplastic change consequent upon 

 change in size. The same consideration raises the 

 query whether simplicity of structure is to be 

 associated with small dimensions, so that fossils of 

 small size, like the Rhynie plants, may be anticipated 

 to be primitive. 



Abnormal Weather in the British Isles. — 

 Exceptional weather conditions in England, either 



NO. 2803, VOL. 112] 



abnormally cold or warm, are of sufficient interest to 

 warrant scientific inquiry, especially with the vie\N 

 ultimately of forecasting such extreme weather 

 changes. The Meteorological Magazine for Juni 

 contains an article by Mr. C. E. P. Brooks of the |j 

 Meteorological Office on " Sea Temperature, Pressure l! 

 Distribution, and Weather of May 1923." It is 

 clearly shown that the abnormally cold and showery 

 weather of May was due to persistent north-westerly 

 winds associated with a steep pressure gradient 

 between an anticyclone over the North Atlantic and 

 a depression over the south of Norway. The author 

 attributes the abnormal conditions to the consequence^ 

 of the abnormal summer of 192 1. That summer, 

 which will be remembered as abnormally fine and 

 dry over England, was marked by open storm% 

 conditions in the Arctic Ocean, which set free larg< 

 quantities of polar ice. This reached Iceland in th< 

 spring of 1922, and lowered the temperature of th( 

 surrounding ocean ; in consequence the pressure 

 rose and the tracks of depressions were driven south- 

 ward, causing the unfavourable British summer of 

 1922. Towards the close of 1922 the bulk of the ice 

 passed into the Labrador current, and this helped to 

 lower the temperature of the Gulf Stream. The 

 combined conditions caused an abnormally cold 

 spring this year in the United States. The mean sea 

 temperature immediately to the westward of the 

 British Isles was about 2°-5 F. below the normal, and 

 this low temperature is said to have been partially 

 the cause of the high pressure over the central 

 Atlantic during May. It is to be hoped that the 

 abnormally hot weather of July, with its associated 

 thunderstorms, will be subjected to a similar searching 

 inquiry. 



Oil and Gas Resources, Osage, Oklahoma. — 

 In Bulletin 686 of the United States Geological 

 Survey is incorporated in one volume the several 

 advance chapters issued between 191 8 and 1920 

 dealing with this important oil-bearing territory in 

 Oklahoma. Apart from the excellent structure- 

 maps included with the geological text, Mr. David 

 White, chief geologist, contributes a significant 

 introduction. The work done on this Osage Reserva- 

 tion is a direct response to what Mr. White rightly 

 terms " the imperative need for increasing to the 

 utmost the petroleum supply of the United States." 

 The area demanded special attention in this connexion 

 for six reasons : it contains a great acreage of un- 

 leased oil-lands, the productivity of certain developed 

 areas is already high, the structures are favourable, 

 the oil is of high quality, transport and refinery 

 facilities are already at hand, and the Ofiice of 

 Indian Affairs (which administers lands held in common 

 by the Osage Indians) has been offering leases to 

 competitive bidders. Unfortunately many of these 

 leases, including some already taken up, are, geologic- 

 ally speaking, unfavourable, while others which have 

 been neglected have great possibilities. In these cir- 

 cumstances organised geological survey was essential, 

 and by means of a system whereby reports were 

 published as soon as delivered by the geologists, 

 prospectors and others interested were able to get 

 first-hand information to guide them in their choice 

 of land. The lucid description of structural principles 

 and geological terms employed, together with the 

 explanatory remarks in the introduction, renders this 

 bulletin much less formal in character than is usualh 

 the case with technical productions, though a short 

 comprehensive summary of the principal geological 

 and economic features of the whole region might 

 have been included with advantage for the benefit 

 of those unconversant with local detail. 



