April 29, 1922] 



NATURE 



561 



Research Items. 



The Dispersion of Flies by Flight. — A definite 

 knowledge of this subject is of importance in measures 

 of control or repression. It is also of significance 

 in the study of the spread of fly-borne diseases. 

 Messrs. Bishopp and Laake {Journ. Agric. Research, 

 xxi. No. 10, Aug. 15, 1 921) have conducted an 

 extensive series of observations with several species 

 of common flies, using an estimated total number of 

 234,000 specimens in the experiments. These were 

 marked by being liberated into bags containing finely 

 powdered red chalk or paint pigment, and afterwards 

 allowed to escape. In order to ascertain the distance 

 of dissemination, baited fly-traps were set at measured 

 distances, in different directions, from the point of 

 Uberation. The experiments carried out show that 

 under rural and urban conditions flies have marked 

 powers of diffusion ; similar results obtain for both 

 the sexes, although in very different proportions in 

 different species. The common house fly, Musca 

 domestica, was recaptured at a distance of more 

 than 1 3 miles from the point of liberation, Chrysomya 

 macellaria 15 miles, and Phormia regina nearly 11 

 miles. The fact that many favourable feeding and 

 breeding grounds were passed over by the flies appears 

 to indicate that, in so far as the above three species 

 are concerned, very evident migratory habits are 

 noticeable. The authors conclude that, under natural 

 conditions, the influence of moderate winds on dis- 

 semination is not of great importance. The speed 

 of flight is evidently considerable ; thus Phormia 

 regina was recovered about 1 1 miles away in less than 

 48 hours after release, and Musca domestica travelled 

 over 6 miles in less than 24 hours. The stimuli 

 affecting dispersion appear to be so blended and 

 mixed as to make it impossible to judge their relative 

 importance. 



The Ascent of S.\p. — Sir J. C. Bose informs us that 

 he has carried out a series of investigations at the 

 Bose Institute, Calcutta, which affords a complete 

 explanation of the phenomenon of the ascent of sap, 

 and its diverse manifestations. The following is a 

 short summary of the results : (i) It is shown that the 

 ascent of sap is a process of physiological activity 

 dependent on the pulsation of living cells inasmuch 

 as it is arrested by the action of poison, either in 

 entire plants or in cut shoots. (2) The active pulsat- 

 ing cells are not confined to the root, but are con- 

 tinued throughout the stem. It has been ascertained 

 that in the stem of Dicotyledons, these cells constitute 

 the cortical layer which abuts upon the endodermis. 

 (3) The velocity of the ascent has been determined by 

 three independent methods, which give concordant 

 results. The ascent takes place in plants even in the 

 complete absence of transpiration. In " varnished " 

 plants this velocity h^s been found sometimes to be 

 as high as 70 metres per hour. (4) The cellular pulsa- 

 tions have been investigated and their characteristics 

 determined from automatic records ; they consist of 

 alternate contractions and expansions. (5) The direc- 

 tion of propulsion is determined by the phase differ- 

 ences of the adjacent cells. The velocity increases 

 with the wave length of the propagated impulse. 

 This wave length is determined experimentally from 

 definite points of electric maxima and minima. En- 

 hancement of velocity is associated with corresponding 

 increase in the wave length. (6) The enhanced rate 

 of ascent is also attended by the increase of amplitude 

 and frequency of cellular pulsations. (7) Ascent of 

 sap depends upon cellular pulsation in tall trees as 

 well as in herbaceous plants. There is, however, in 

 the former the special adaptation of the woody tissue 

 which serves as a reservoir to meet the excessive 



NO. 2739, VOL. 109] 



demand for water in the season of active transpiration. 

 When this reservoir is more or less depleted, the 

 phenomenon of " negative pressure " is manifested. 



Norwegian Explorations in Spitsbergen. In 



191 7 the Norwegian Government decided to under- 

 take the systematic survey and exploration of the 

 western part of the mainland of Spitsbergen between 

 Ice Fjord and the South Cape. This was in con- 

 tinuance of previous Norwegian work under the 

 auspices of the Prince of Monaco on the west coast 

 between the north of Spitsbergen and Ice Fjord. 

 The work was to include geological exploration and 

 hydrographical survey in coastal waters, where 

 this was incomplete. In " Revue de Geographie 

 Annuelle," Tome ix.. Fascicules iv.-v., 1922, Mr. A. 

 Hoel gives a full account of the surveys made in 

 1919, 1920, and 1921, when he was in charge, and 

 a summary of the whole work, which is now virtually 

 completed after five summers in the field. Only a 

 few small gaps in the survey between Horn Sound 

 and the South Cape remain to be filled in. Alto- 

 gether some 4800 sq. kilometres of land surface 

 have been surveyed. The most striking geological 

 results are the proof of the Ordovician age of the Hecla 

 Hook beds of the west coast, and the discovery 

 that beds ranging from Carboniferous to Tertiary- 

 ages form the greater part of the coastal region 

 south of Horn Sound where the Hecla Hook beds 

 were supposed to predominate as they do farther 

 north. The botanical researches, of which some 

 important results have already been published, 

 promise to be of great interest. 



Tertiary Fossils of Peru. — We have received 

 a copy of " Illustrations of the Tertiary Fossils of 

 Peru," by H. Woods, T. Wayland Vaughan, and 

 J. A. Cushman. It consists of twenty-four plates 

 of fossils and their explanations, without any indica- 

 tion of the source of issue or the possibility of 

 accompanying text. We understand, however, that 

 they are intended to illustrate a forthcoming work on 

 the " Geology of N.W. Peru," by Dr. T. O. Bosworth 

 The first twenty plates deal with MoUusca, and for 

 these Mr. Woods is responsible, Mr. Vaughan answer- 

 ing for three of Corals, and Mt. Cushman for the 

 one of Foraminifera. This separate issue will be 

 very welcome to palaeontological students, who will 

 at once recognise the wonderful similarity of these 

 Peruvian fossils to those of our British Oligocene 

 and Eocene ; indeed one, Venericardia planicosta, is 

 said to be identical, while there is a Clavilithes, 

 which the author, doubtless on good grounds, cites 

 as a new species, but which one might be forgiven 

 for mistaking for C. longcevus. Mr. T. A. Brock, the 

 draughtsman of the plates, is to be congratulated on 

 his beautiful figures, which have been most admirably 

 reproduced ; we have seen nothmg better. 



Records of Pal^ontological Research. It is 



well from time to time to emphasise the value of the 

 simple paper-bound guides to the British Museum" 

 collections as means of keeping the student in touch 

 with the developments of research. The tenth edition 

 of " A Guide to the Fossil Reptiles, Amphibians, 

 and Fishes " has just appeared, with 8 plates and 117 

 text-figures, price 2s. (1922). Here will be found 

 the Downtonian ostracoderms of Lanarkshire, the 

 problematic Palaeospondylus, Ichthyosaurus from 

 Lyme Regis, clothed in a habit drawn from German 

 specimens, and Tritylodon, placed clearly with the 

 theriodonts. One of the plates shows the immense 

 proportions of the hind limb and tail of the Cetiosaurus 

 discovered by A. L. Leeds near Peterborough. 



