January i, 1903] 



NA TURE 



209 



An expedition sent by the New York Botanical Garden to 

 Nova Scotia and Newfoundland has secured, the Scientific 

 American states, 12,000 specimens of more than 2000 species of 

 plants. A third of the specimens are marine plants. Another 

 expedition sent to north Montana by the same enterprising 

 institution has done much in the interest of scientific botany. 

 Manj alpine forms of plants were discovered. Ample statistics 

 were secured establishing the variation of plant life caused by 

 temperature and latitude, and of the general vertical distribution 

 of flora. 



Referring to Mr. Backhouse's letter on sunset glows in 

 last week's Nature (p. 174), the Rev. G. J. Bridges, writing 

 from Salisbury, says : — " In addition to the colour growing less 

 vivid, the ' colouring ' does not occupy so much space as in the 

 Krakatoa glows. It occurs much sooner after sunset and much 

 nearer sunrise than in the case of those which occurred in 18S3. 

 . . . The dust wisps are so much more defined of late that it is 

 difficult to distinguish them from faint streaks of strata except 

 by position, which appears to be always horizontal and corre- 

 sponding to the curvature of the earth." 



In most of our colonies, more particularly those which are 

 concerned with agriculture, the official botanical staff is no 

 longer considered to be complete without a specialist in plant 

 diseases. The reports and pamphlets embodying the researches 

 of these specialists bear evidence of valuable and important work. 

 An account of the fungus diseases which attack stone-fruit trees 

 in Australia has been prepared by Mr. D. McAlpine. The 

 principal diseases are described at some length and illustrated 

 with very excellent coloured plates. These present diagnoses 

 suited to the farmer whose scientific knowledge is limited, and 

 methods of treatment are suggested and explained. Besides, 

 there is added an account of many less common fungi also 

 destructive to trees bearing stone-fruit, which presupposes a 

 certain amount of botanical training. 



The report of the Director of the Botanic Gardens, Sydney, 

 N.S.W., for 1901, besides dealing with matters appertaining to 

 the Botanic Gardens, includes the improvements effected in the 

 various public gardens which come under his control. An event 

 of considerable importance was the opening of new buildings 

 which had been erected in order to accommodate the National 

 Herbarium and provide space for a botanical museum. The 

 latter occupies one of three large rooms, while the other two 

 are set apart for the cryptogamic and phanerogamic herbaria 

 respectively. An interesting feature of the museum is a collec- 

 tion of local plants ; also due prominence has been given to 

 characteristic Australian plants, such as the Acacia?, Eucalypti, 

 various genera of the Proteacere, and Coniferce. Reference is 

 made to the trees planted by their Royal Highnesses the Duke 

 and Duchess of Cornwall and York on the occasion of their 

 visit to Sydney. 



Mr. F. C. Constable directs attention to the serious dis- 

 advantages of the common practice of hanging on the walls of 

 schoolrooms maps of various countries of widely differing 

 areas, all drawn to different scales, with the result that the 

 countries appear, approximately, of the same size. One of the 

 direct consequences of this custom is that comparatively few 

 educated persons can give the relative sizes of, say, England 

 and Africa, of Canada, Australia and British India, with any 

 approach to accuracy. This defect in geographical teaching is 

 by some teachers avoided by the use of wall-maps of the con- 

 tinents having printed in the corner a map of England to the 

 same scale to serve as a key. It should not be difficult for 

 teachers to prevent their pupils from obtaining an erroneous 

 sense of proportion. 



no. 1 73 1, VOL. 67] 



A disease resembling " farcy," the cutaneous form of 

 glanders, has been found to be prevalent in the Philippines. It 

 is, however, not glanders, but is due to a blastomycetic para- 

 site which can be detected in the lesions, and may be isolated 

 and cultivated from these, though with some difficulty. 



The Punjab Government has been compelled temporarily to 

 suspend its scheme for extensive inoculation against plague. A 

 portion of the vaccine fluid became contaminated and induced 

 tetanus in a small number of persons who were inoculated with 

 it. During the month of October, no fewer than 120,000 people 

 were voluntarily inoculated, and it had been intended to supply 

 70,000 doses of the vaccine fluid per diem had not this un 

 fortunate mishap occurred. 



Sir William MacGregor, in an address delivered to th 

 students of medicine of Glasgow University, dealt e- ecially 

 with the prophylaxis of malaria. As the outcome of his great 

 experience, he recommended the preventive use of quinine in 

 coses amounting to at least 15 grains a week. He stated that 

 in Lagos the radical method of Ross for the extermination of 

 mosquitos is being pursued by filling in the swamps with sandy 

 soil. The large pools which cannot be drained at present have 

 crude petroleum pat on the surface periodically. Empty tins 

 and similar rubbish are removed, and receptacles for drinking 

 water are kept carefully covered. Native boys are now being 

 employed as mosquito catchers, and should be upon the fixed 

 establishment of every European resident in such a place as 

 Lagos. 



Sir Charles Todd has supplied the following notes on the 

 rainfall during the past winter (April to September) in South 

 Australia :— As compared with the average at thirty-seven selected 1 

 stations distributed over the colony, the six months' fall is, 

 without exception, far below the average amount. It is, in fact, 

 one of the driest years ever experienced- so far as all the 

 northern areas are concerned it is the driest— and the same 

 applies to many parts of the south. At twenty-four out 

 of the thirty-seven stations, the winter of 1902 is the driest 

 on record, whilst at eight others only one other year was drier. 

 At Adelaide, where the records go back to 1839, during 

 the six months April to September, 1902, we have registered 

 only9'49 in., or 4^64 in. under the general average ; in 1891, 

 however, we only had 7'62 in. in the same time : in 1869, 873 

 in., and in 1876, 9^24 in., whilst in 1SS6 we recorded 943, 

 about the same as in 1902, so that as regards the city that 

 year is not a record. 



Many theories have been put forward to account for the so- 

 called "black and white dot phenomenon" visible on diatom 

 valves under high powers of the microscope. A discussion of 

 several of these theories is given by Mr. Julius Rheinberg in the 

 Journal of the Quekett Microscopical Club for November. After 

 discarding the hypothesis of spherical aberration of the object on 

 the ground thit it does not fully account for the variations 

 observed, Mr. Rheinberg gives reasons for his opinion that the 

 effects are due to crossing of cones of light and darkness arising 

 from total reflection beyond the critical angle between the mount- 

 ing medium and the diatom. If this hypothesis is accepted, the 

 dots on the diatom must be regarded as perforations the depths 

 of which are greater than their breadth ; this appears to be Mr. 

 Rheinberg's view. Lastly, a diagram of the critical angles of 

 different media relative to diatom silex and of the amounts of 

 light totally reflected agrees fairly well with observation. 



Messrs. Elster and Geitel, in a recent number of the 

 Physikalische Zeilschrift, describe an improvement in Exner's 

 electroscope rendering the reading of the deflections more 

 accurate. To one of the glass sides of the instrument a mirror 



