374 



NATURE 



[May 20, 1920 



about 140 O.D., being 20 ft. lower than that of the 

 Boyn Hill terrace in the neighbourhood. 



Mr. Herbert Bolton: Enlarged photographs of fossil 

 insects from the British Coal Measures. The first 

 recorded fossil palaeozoic insect from any country was 

 discovered in the Coal Measures of Coalbrookdale in 

 the early part of last century. In 1908 only twelve 

 additional types from Great Britain had been made 

 known. Mr. Bolton's researches during the last ten 

 years have revealed the fact that at least fifty dis- 

 tinct types had lain unrecognised in various museums 

 and private collections. The photographs exhibited 



were made by Mr. J. VV. Tutcher. 



Dr. W. K. Spencer : Palaeozoic starfish and their 

 habits. Recent work by the Danish Fisheries Board 

 upon the habits of recent forms throws considerable 

 light on the mode of life of the fossil starfish. Recent 

 starfish can be divided into (i) starfish, carnivores, 

 and (2) brittle starfish, detritus feeders living on vege- 

 table remains in the mud on the sea-bottom or on 

 very young marine animals. Both these series of 

 forms are modified for their respective mode of life. 

 The exhibit showed that both classes of forms were 

 present in the palaeozoic rocks, and that some of the 

 forms from the very old rocks were strikingly similar 

 in mode of life to those of the present day. Forms 

 which are transitional in structure between the tVk'o 

 series were also shown. 



Dr. F. A. Bather: Stalked Echinoderms with a 

 horizontal habit of growth. In a normal stalked 

 Echinoderm the stalk, body, and five arms are sym- 

 metrical about the long axis, which is vertical, and 

 the waste products are carried away from the vent 

 at the upper end. But all the Cystids found in the 

 Upper Ordovician starfish bed of Girvan, Ayrshire, 

 have a body flattened in the plane of the stalk, and 

 this shows that the long axis was stretched hori- 

 zontally. Extreme modification for this mode of life 

 is reached in three different ways by three genera of 

 diverse origin : Dendrocystis, which floated, with its 

 stalk attached probably to seaweed ; Pleurocystis, 

 which was possibly attached, but rested its body on 

 the sea-floor ; and Cothurnocystis, probably free, with 

 its body resting on the sand by short legs. Cothurno- 

 cystis had no arms, but from thirteen to forty-two 

 mouth-slits. 



Mr. R. D. Oldham: Model to illustrate an hypo- 

 thesis of the origin of mountains. If the variation 

 in density, and consequently in bulk, of the matter 

 underlying mountain ranges is also the cause of the 

 surface elevation, and if the outer crust is possessed 

 of a considerable degree of strength and stiffness, 

 resting on material of a more yielding character, sys- 

 tematic departures from complete equivalence of sur- 

 face elevation and compensation would result. The 

 model is intended to visualise this. 



Mr. A. V. Hill: Thermopiles for investigating the 

 thermal or the thermo-elastic properties of muscles. 

 When a muscle is stimulated, heat is produced in 

 four separate stages : (a) in the development, (b) in 

 the maintenance and (c) in the disappearance of the 

 mechanical response, and (d) in the processes of 

 oxidative recovery. This heat-production is recorded 

 by employing delicate insulated thermopiles and a 

 sensitive galvanometer with photog'raphic recording. 



Prof. E. Mellanby : The effect of an accessory food 

 factor (vitamine) on : (i) The production of rickets 

 in puppies. Soft bones and other signs of rickets 

 are produced in puppies (five to eight weeks old) 

 when fed on diets unbalanced in that they contain 

 too little of an accessory food factor (vitamine) — 

 probably fat-soluble A. ' (2) The development^ of 

 the teeth in puppies. Diets deficient in a vitamine, 

 possibly fat-soluble A, produ^^e teeth defectively cal- 

 NO. 2638, VOL. 105] 



cified and more or less irregularly placed in soft 

 jaws. 



Mr. Julian Huxley and Mr. Lancelot T. Hogben: 

 The relation of the thyroid to metamorphosis. The 

 exhibits illustrated (i) acceleration of frog's meta- 

 morphosis by thyroid-feeding ; {2) metamorphic 

 changes in the axolotl induced by iodine; and 

 (3) metamorphosis of Amblystoma by thyroid-feeding 

 with a control. 



Prof. R. Ne-ivstead: Samples of mite-infested flour. 

 Flour which is heavily invested with mites (chieflv 

 Aleurobius farinae) is certainly ruined. !t has a most 

 unpleasant odour, and in the early stages becomes 

 discoloured owing to the quantities of excrement with 

 which it is charged. Prevention from attack may be 

 secured by storing flour with a low moisture content, 

 i.e. below 11 per cent, in the temperate zone and 

 from 6-7 per cent, in the tropics. 



Prof. G. H. F. Ntittall and Dr. D. Keilin: 

 Hermaphroditism in Pediculus humanus. The 

 microscopic specimens illustrated hermaphrodites of 

 intersexual type and included a complete series of 

 forms from those of male type to those of female 

 type, the co-existing characters of both sexes being 

 present to a varying degree. The intersexual forms 

 which occur among Pediculi in Nature are derived 

 from the crossing of the races of P. humanus. i.e. 

 capitis and corporis. Some of these crosses yield up 

 to 20 per cent, of hermaphrodites. 



Mr. J. E. Barnard: Photomicrographs obtained by 

 means of ultra-violet light. It is well known that 

 resolving power in the microscope is dependent on 

 the N.A. of the objective and the wave-length of the 

 light used. Decrease of wave-length results in pro- 

 portionate increase of resolution, and this method 

 opens up a promising field of investigation. There is 

 the further advantage that biological preparations, 

 particularly bacteria and other micro-organisms, are 

 sufficiently opaque to ultra-violet light of suitable 

 wave-length to render staining unnecessary. The result 

 is that they can be photographed in the living state. 



Dr. J. C. Mottram and Dr. E. A. Cockayne: 

 Demonstration of fluorescence in Lepidoptera by 

 ultra-violet radiation. The beam of ultra-violet rays 

 is produced by means of a quartz mercury vapour 

 lamp in a box with a window of the glass invented 

 by Prof. Wood. This is transparent to radiation of 

 wave-lengths lying between 3900 and 3100 A.V., but 

 opaque to light. Onlv a small proportion of the 

 Lepidoptera examined have proved to be fluorescent, 

 and all of these are whitish or yellow in colour. 



The Botany Department, Imperial College of 

 Science and Technology : Recording porometer. This 

 instrument records the rate at which air, under 

 slightly reduced pressure, is drawn through the stomata 

 (pores) into a gflass cup fixed on the .under-surface of 

 the leaf. It thus gives a measure of the size of these 

 pores. Every time a bubble of the air so drawn in 

 escapes from the lower tube it momentarily makes 

 contact between the mercury and a platinum wire ; 

 the current passing then moves the recording pen on 

 the surface of the revolving drum. 



The Cambridge and Paul Instrument Co., Ltd.: 

 A new microtome. This instrument is designed on 

 similar lines to the well-known Cambridge "rocking" 

 microtome, but the object is in a much more con- 

 venient position for observation and orientation, and 

 the microtome cuts plane sections in either paraffin 

 or celloidin, and the' design is suitable for freezing 

 obiects bv ethyl chloride spray. 



The Roval Geograi>hical ' Society : Method of 

 mounting panoramic views of wnde anfle. A photo- 

 graphic panorama of wide angle, made up from_ a 

 number of separate pictures, gives a false impression 



