248 



NA TURE 



[August 18, 1923 



Research Items. 



The Swiss National Park and its Moli.usca. — 

 First mooted in 1906, a National Park for Switzerland 

 was finally established in January 1919. It is situate 

 in the Lower Engadine, almost on the extreme 

 eastern border of Switzerland, and abutting on the 

 Italian frontier. It comprises an area of about 

 151-5 sq. km., and has been put in the charge of a 

 Commission, which has wisely decided on a complete 

 investigation of its fauna, flora, etc., a task which 

 the Schweizerische Naturforschende Gesellschaft has 

 undertaken to carry out. For the purposes of this 

 survey, however, it has been resolved to include the 

 territory to the north of the Park down to the banks 

 of the Inn, as well as some to the east, so as to furnish 

 a more satisfactory physical area to deal with as a 

 whole. The first portion of this undertaking, the 

 " Molluscan Fauna," by Ernst Biitikofer, has just 

 been published by the Schweizerische Naturforsche;ide 

 Gesellschaft in Bd. Iv. of their Denkschriften. If 

 this be a fair sample the complete work will be well 

 worthy of its authors. Following a general account 

 of the characters of the eleven districts into which, 

 for purposes of description, the district has been 

 divided, come the molluscan fauna of each, a syste- 

 matic description of the various species and varieties, 

 with tables of their horizontal and vertical distribu- 

 tion, and an excellent bibliography. Close on eighty 

 forms, if we include those in the appendix, are dealt 

 with, and the photographs of shells are mostly parti- 

 cularly good. 



Protozoa and Potato Mosaic. — As recently 

 reported in Nature (July 21, p. iii), Ray Nelson has 

 reported in America that a protozoal organism is 

 associated with the phloem of potato plants affected 

 by the disease known as mosaic, which is usually 

 grouped among the " virus " diseases in which the 

 causal organism is assumed to be ultra-microscopic. 

 The July issue of Phytopathology, the journal issued 

 by the American Phytopathological Society, contains 

 no less tlian four brief papers, with which the names 

 of seven investigators are associated, all pointing out 

 that the structures described by Nelson are also 

 present in the phloem of Solanaceous plants which 

 are not affected by mosaic but, so far as can be 

 determined, are perfectly healthy. There seems to 

 be little doubt that Nelson has redescribed and 

 photographed peculiar protoplasmic inclusions, pre- 

 sent in the phloem of some Angiosperms but not in 

 all, and which, as Irving W. Bailey and other writers 

 point out in Phytopathology, are probably identical 

 with the " slime bodies " described by Strasburger 

 (in i8gi) in the phloem of Robinia Pseiidacacia. 

 These " slime bodies " do not seem to be identical 

 with nuclei, though they often are seen in contact 

 with them. Ernst W. Schmidt, in his recent mono- 

 graph upon the Angiosperm sieve-tubes (Jena, 191 7), 

 concluded that the nucleus was typically present in 

 the Angiosperm sieve-tube. Possibly this recent 

 American rediscovery of these other cytoplasmic 

 inclusions will lead to a re-exploration of the cytology 

 of the sieve-tube, a subject which would seem to be 

 by no means exhausted. 



Popi.ARS. — Forestry Commission Bulletin No. 5, 

 just issued by H.M. Stationery Office, price is. 6d., is 

 a remarkably full account of the different poplars 

 which are suitable for the production of timber on a 

 commercial scale in Great Britain. The first chapter, 

 due to Prof. A. Henry, is concerned with their 

 botanical description, and is illustrated with two 

 plates, showing clearly the distinctive characters of 



NO. 2807, VOL. 112] 



the twigs and leaves of the twelve important species 

 and hybrids. The second chapter, by Mr. W. H. 

 Guillebaud, who specially investigated the growth of 

 poplars in the north of France, is devoted to silvi- 

 culture, and discusses fully propagation, planting, 

 thinning, pruning, rate of growth and yield. In the 

 third chapter. Dr. J. W. Munro deals with injurious 

 insects and Mr. W. E. Hiley with fungi and bacterial 

 diseases. The last chapter, by Mr. W. H. Dallimore 

 of Kew, is an admirable account of the character and 

 uses of poplar wood, and should prove of great 

 interest to both landowners and manufacturers, as 

 the use of home-grown poplar timber is capable of 

 great extension. For example, the wood of asr)en is 

 indispensable for the match industry, and has 

 hitherto been mainly imp)orted from Northern Russia. 

 The recent plantation on a large scale of this tree in 

 Argyllshire by Messrs. Bryant and May indicates 

 that supplies of aspen timber from abroad at a 

 reasonable price cannot in the future be depended 

 upon. 



Upper-Air Observations in North Russia. — A 

 Professional Note, vol. 3, No. 32, carried out by 

 Mr. W. H. Pick, has been published on the above by 

 the Meteorological Office, Air Ministry. The observa- 

 tions are based upon pilot balloon ascents between 

 February 25 and September 13, 1919, at three stations 

 in north-west Russia. The stations are Murmansk, 

 at the head of the Kola Creek, in latitude about 69" N., 

 Archangel on the south-western coast of the White 

 Sea, in latitude 64° 33' N., and Lumbushi on the 

 Murman Railway, in latitude about 68° N. The 

 ascents were all carried out with one theodolite only, 

 the balloon being given a vertical lift of, theoretically, 

 500 ft. per minute. The high latitude in which the 

 observations were obtained renders them of value. 

 There were at Murmansk 57 occasions on which the 

 surface wind was in the north-east quadrant, and on 10 

 of these— that is, 17-5 per cent, of the total — the wind 

 backed continuously up to 2000 feet. On the other 

 hand, there were 164 occasions on which the surface 

 wind was not in the north-east quadrant, and in only 

 5 of these — that is, 3-0 per cent, of the whole — did 

 the wind back continuously upward. At Murmansk 

 three ascents reached to a height of 40,000 feet, where 

 two of the winds were N.\\'. and one S.W. Two 

 ascents reached to 60,000 ft., where both winds were 

 S.W. Seven ascents reached 20,000 ft., at that 

 height four of the winds were S.W. ^nd two N.W. 

 Of the ascents carried out at Archangel only one 

 reached 20,000 ft., where the wind was southerly. 

 Of the ascents at Lumbushi, six attained a height of 

 20,000 ft., giving two north-westerly winds, three 

 north-easterly, and one southerly. 



The Climate of Khartoum. — Physical Depart- 

 ment paper No. 9, prepared by Mr. L. J. Sutton, has 

 recently been issued by the Ministry of Public Works, 

 Egj'pt. The discussion deals with the meteorology 

 of Khartoum, which place was installed as a second- 

 order station in 1900, and is approximately 390 metres 

 above sea-level. Maps of isobars are given for the 

 several months which show the normal distribution 

 of pressure over the surrounding region, which is of 

 great help in following the changes of weather con- 

 ditions which occur at Khartoum in the different 

 seasons. It is during the period from the middle of 

 June to September that the weather conditions are 

 most disturbed. Thunder-storms and haboobs, or 

 storms of wind, are frequent, and the short rainy 

 season is experienced. In October to May there is 



