68 



NA TURE 



[May 19, 1904 



Table III. — Effect on Milk Sugar of Pancreatic Juice from 

 " Biscuit-fed " dogs, which had received Subcutaneous 

 Injections during three days of Extracts of the Mucous 

 Membrane of " Milk-fed " dogs. 



The figures represent c.c. of lactose solution which reduced 

 50 c.c. Pavy's solution. 



Here then at last we have some glimpse into the 

 mechanism of the adaptation of the pancreas to the nature 

 of the food, .^s the result of injection of lactose some sub- 

 stance which we may call x is produced in the mucous 

 membrane of the small intestine. This substance is carried 

 by the blood to the pancreas, and there slowly gives rise 

 to the formation of lactase which is turned out in the juice 

 when secretion is e.Kcited by the entry of acid chyme into 

 the duodenum. We have no knowledge as yet as to the 

 nature of this substance x. All we can say is that it is 

 destroyed at a boiling temperature, since boiled extracts 

 of the mucous membrane of milk-fed dogs do not, when 

 subcutaneously injected, cause the appearance of any 

 lactase in the pancreatic juice of biscuit-fed dogs. 



Whether the qualitative adaptation of the juice in respect 

 of its trypsin, ainylopsin, and steapsin is carried out in a 

 similar fashion we cannot as yet say. We hope that an 

 investigation of the mechanism of this adaptation, which 

 is now proceeding, may throw light, not only on the factors 

 involved, but also on the nature of the substance which is 

 formed in the mucous membrane, and has this marked effect 

 on the activity of the pancreatic cells. Involving, as it 

 does, two distinct sets of cells, this chemical adaptation is 

 more complex than any yet investigated, and shows the 

 intimate relation which must exist between the chemical 

 activities of very different organs of the body. 



THE ROYAL SOCIETY CONVERSAZIONE. 



'T^HE Royal Society conversazione was held in the rooms 

 of the Society at Burlington House on Friday last. 

 May 13. Many exhibits illustrating methods and results 

 of recent scientific progress were on view, and are briefly 

 described in the following abstract of the official catalogue. 

 .So far as possible the exhibits representing related subjects 

 are here grouped together. 



In the course of the evening, lantern demonstrations were' 

 given in the meeting room of the society. Prof. W. A. 

 Herdman gave an account of the recent investigation of 

 the Ceylon pearl fisheries ; Mr. Francis Fox showed lantern 

 slides, illustrative of (i) operations at the Simplon Tunnel ; 

 (2) the Victoria Falls and gorge of the River Zambesi, and 

 proposed bridge: and the Hon. C. .\. Parsons, F.R.S., gave 

 .1 demonstration of the auxetophone. This instrument is 

 ;m air operated valve which is used for a reproducer in 

 gramophones and phonographs, and replaces the usual re- 

 producing diaphragm in such machines. The application of 

 this valve to the violin was shown, selections of music, 

 vocal and instrumental, being played on the auxetophone. 

 The following is a classified list of the other exhibits : — 

 The differentiator, a machine recording as a curve the 

 values of the rate of change of any variable quantity which 

 can be represented by a curve: Dr. J. Erskine-Murray. 

 When the machine is guided along any curve it auto- 



NO. 1803, VOL. 70] 



matically traces another which represents the rate of change 

 of the quantity represented by the first curve. Thus, if the 

 population of a country at various dates be plotted on paper 

 the derived curve shows the rate at which the populationi 

 is increasing or decreasing at every date during the period 

 chosen. — Twin-elliptic figures showing change of phase in 

 one or both ellipses : .Mr. Joseph Goold. — .\ radial area- 

 scale : Mr. R. W. K. Edwards. A contrivance for finding: 

 the area of a plane figure by means of a transparency. 



Sensitive barograph, for the study of minor variations- 

 of atmospheric pressure : Dr. W. N. Shaw, F.R.S. The 

 instrument show's the details of comparatively rapid fluctu- 

 ations of pressure such as are often indicated in the baro- 

 metric diagram of the Times. — (i) Traces obtained from 

 self-recording instruments sent up by means of kites, (2)1 

 self-recording instruments from which the traces w'ere 

 obtained : Mr. W. H. Dines. In the recording instruments- 

 designed by M. Teisserenc de Bort, the height is obtained 

 from an exhausted aneroid box, and the temperature from 

 a Bourdon tube. In the recording instruments designed by 

 the exhibitor, the height is obtained from a fair sized aneroidl 

 box of thin metal containing air. .\ temperature correction! 

 is necessary, but the position of the pen is dependent oni 

 the elasticity of the enclosed air. — Photographs of clouds : 

 Commander D. Wilson-Barker. — Models and photographs- 

 of large hailstones : the Royal Meteorological Society. 



Photographs and diagrams illustrating solar and meteor- 

 ological changes, and a series of photographs to determine- 

 the relative temperatures of the stars: Sir J. Norman 

 Lockyer, K.C.B., F.R.S. The exhibit illustrated (1) en- 

 larged pictures of the sun in " K " light taken with the 

 spectroheliograph of the Solar Physics Observatory. (2)' 

 The results of a discussion of sun-spot distribution. (3} 

 The relationship between the positions of solar prominences- 

 and the different forms of the corona. (4) The different 

 types, and their distribution, of the short period barometric 

 pressure variation over the earth's surface. (5) The close- 

 connection between the change of barometric pressure andi 

 rainfall. (6) Series of photographs taken with a quartz- 

 calcite prismatic camera of 2 inches aperture and 18 inches- 

 focal length to determine the relative temperatures of stars. 

 — The Narraburra siderite. New South Wales : Prof. A. 

 Liversidge, F.R.S. This exhibit included photographs of 

 the siderite, and photographs of etched sections to show the 

 changes in the internal structure. The composition of the 

 siderite was : — iron 88-605, nickel 9 741, cobalt o 474, copper 

 o-ooq, phosphorus 0-429, sulphur traces, resinous matter 

 0-008, insoluble in HCl. 0720 = 99-906. Traces of gold and 

 of the platinum metals appeared also to be present. — Trans- 

 parencies and prints in illustration of a photographic atlas 

 of the heavens ; photographed at the Royal Observatory, 

 Cape Town, 1903-4: Mr. J. Franklin-Adams. — Ten trans- 

 parencies from negatives taken with the Rumford spectro- 

 heliograph of the Yerkes Observatory by Prof. G. E. Hale 

 and Mr. F. Ellerman : the Royal Astronomical Society. 



Examples showing the application of natural colour photo- 

 graphy to the production of lantern slides of spectra for 

 lecture and educational purposes : Mr. E. Sanger-Shepherd. 

 Negatives are taken through three colour filters, admitting 

 light of the three primary colour sensations — red, green and 

 blue-violet, in accordance with the power of the respective 

 sensations to excite the eye. From these negatives gelatin 

 relief prints are made upon a special film, each relief being 

 soaked in a water-colour ink of the complementary colour 

 to the sensation which it represents. These reliefs whilst 

 still wet are successively applied to a mordanted gelatinised 

 glass plate. The inks transfer to the mordanted gelatin 

 film, and the result is a natural colour photograph, consist-^ 

 ing of nothing but the colouring matter securely locked up 

 in a single film of gelatin. — Colour photographs shown by 

 spectrum colours : Sir W. de W. .Abney, K.C.B., F.R.S. 

 The ordinary three-colour photographs are shown in a triple 

 lantern, one image being tinted by the light coming through 

 red glass, another by that through green glass, and the third 

 by that through blue glass. The new method substitutes 

 spectrum colours for the three glasses, with the result that 

 tlie colours on the screen are much purer and truer. — High 

 power microscopy : Mr. J. W. Gordon. The apparatus 

 consists of a compounding drawtube and oscillating screen, 

 as proposed in .Mr. J. W. Gordon's paper on the Helmholtz 



