354 



NATURE 



[November 25, 1915 



A series of papers on the metabolism of amino- 

 acids in the organism is contributed by Dr. U. 

 Lombroso and his collaborators (vol. xxiv., i., 148, 

 475' 863, and 870). Dr. A. Clementi (vol. xxiv., i., 

 972) has studied the action of proteoclastic enzymes on 

 polypeptides, and (vol. xxiv., i., 55) the introduction 

 of the guanidine nucleus into the molecule of poly- 

 peptides and its significance in physiology. 



Amongst papers in pure organic chemistry, the 

 following may be mentioned. E. Sernagiotto has 

 studied in detail carvone camphor, a substance formed 

 by the isomeric change of carvone when exposed to 

 light in aqueous alcoholic solution. A. Angeli deals 

 with the properties of certain azoxyphenols and of 

 certain aldehydic compounds, V. Paolini and L. 

 Devizia with the isomeric linalools and the resolution 

 of the inactive form into its optically active com- 

 ponents. L. Mascarelli and F. Negrisoli describe the 

 resolution of decahydroquinoline into its optical anti- 

 podes. 



In inorganic chemistry, Dr. G. Ponti describes in- 

 vestigations of the exhalations from Mount Etna ; 

 L. Cambi and G. Sperone have studied the properties 

 of calcium amalgam and give measurements of its 

 electromotive force. The electromotive force of mag- 

 nesium amalgam forms the subject of a separate 

 paper by L. Cambi. 



In physics, A. Lo Surdo has studied the electrical 

 field in the Hittorf-Crookes space, and the electrical 

 decomposition of spectral lines. A. Venturi gives 

 measurements of gravity carried out in Sicily in 1910, 

 and U. Cisotti contributes a mathematical study of 

 new types of permanent periodic and rotational waves. 

 G. C. Trabacchi deals with the Hall effect in alloys 

 of tellurium and bismuth, and P. Cardani describes 

 a method of stabilising the action of Rontgen tubes 

 by absorption of the carbon dioxide. 



In the biological sciences, B. Grassi deals with 

 phylloxera, G. Tizzoni with the significance of poly- 

 morphism in identifying the streptobacillus of 

 pellagra, and R. Perotti with the morphological 

 variation of Mycoderma vini. 



W. A. D. 



PHYSIOLOGY AT THE BRITISH 

 ASSOCIATION. 

 A FTER the president's address the reports of 

 ■'*■ several research committees were received. 

 Prof. Waller demonstrated a small apparatus he had 

 devised for the convenient administration of known 

 percentages of chloroform. The regulation of the 

 dose is easily effected, and anaesthesia may be safely 

 induced by the patient himself, the mask falling off 

 the face when the patient is sufficiently under chloro- 

 form. 



In the report of the committee investigating the 

 electromotive phenomena of plants Prof. Waller de- 

 scribed an electrical method of testing the vitality of 

 seeds. The size of the electrical response is directly 

 proportional to the amount of vitality. The method 

 is a great improvement upon existing methods, and 

 should prove of commercial value in the testing of 

 seeds. 



Prof. Moore gave a paper on the action of light 

 upon certain inorganic and organic substances. lie 

 reviewed the action of chlorophyll in photosynthesis, 

 and showed how similar action could be obtained by 

 the use of inorganic salts in place of chlorophyll. 

 Prof. Moore found that acid salts, and especially iron 

 salts, are most effective, the action being greatest 

 when the colloidal surface is at a maximum. Chloro- 

 phyll itself is not the essential element in photosyn- 

 thesis, but the colloidal salts in the chloroplast. Iron 



NO. 2404, VOL. 96] 



salts are abundant in many of the lower plants, and 

 enable these to make use of the action of light. 



Dr. T. W. Edridge-Green, in a communication 

 entitled " Some Fundamental Facts of Vision and 

 Colour Vision," attacked the prevalent assumptions 

 that the rods of the retina are percipient elements, 

 and that there arc fundamental colour sensations which 

 by their mixture give rise to other colour sensations. 

 He adduced a number of arguments which he con- 

 sidered destructive of these theories. 



Dr. T. W. Graham Brown then illustrated by 

 lantern slides the effects of removal of the post-central 

 gyrus of both sides of the brain upon the movements 

 of a chimpanzee. Shortly after operation the chim- 

 panzee was able to swing from the bars of the cage, 

 using either hand with no sign of inco-ordination. 

 A month after operation the animal showed no 

 symptoms, was able to choose the right key from a 

 bunch, insert it in the keyhole, and unlock and open 

 the door of its room. 



Prof. Herring described the effects of thyroidectomy 

 and thyroid-feeding upon the adrenin content of the 

 suprarenals. The adrenin was tested by the action 

 of extracts of the suprarenals upon the blood-pressure 

 of pithed cats after the method employed by Elliott. 

 In a further series the amount of adrenin was 

 measured- by Folin's colorimetric process, and expressed 

 in amount per kilo, bodj-weight. Thyroidectomy 

 reduced the adrenin content considerably, but, when 

 compared with the adrenin content of control animals 

 similarly operated on except for the thyroids being left, 

 it was found there was little difference. In animals 

 which tolerate thyroidectomy, e.g. rabbits, there was 

 little difference between the adrenin contents of thy- 

 roidectomised and control operated-upon animals a 

 month after operation. Thyroid-feeding, on the other 

 hand, in every case increased the adrenin content above 

 that of the normal animal, and extracts of the supra- 

 renals from th3a-oid-fed animals gave greater effects 

 upon blood-pressure than similarly prepared extracts 

 from the suprarenals of normal animals. 



On Thursday Prof. Bayliss opened the day's pro- 

 ceedings by a paper on "The Mode of Action of 

 Urease." He finds that urease is active in solutions 

 in which it is insoluble, e.g. strong alcohol, and there- 

 fore acts at its surface by adsorbing urea. Water 

 increases the rate of reaction by mass action or by 

 the intervention of molecular forces in the act of con- 

 densation. On this assumption the action of various 

 substances on the rate of reaction may be explained 

 in two ways. The one action changes the degree of 

 colloidal dispersion, and so alters the extent of active 

 surface. Electrolytes show this action either by in- 

 creasing dispersion and so accelerating the reaction, 

 or by decreasing the surface by aggregation or in- 

 cipient precipitation and so retarding the reaction. 

 Weak acid and phosphate accelerate the reaction by 

 increasing dispersion ; multivalent ions, such as 

 lanthanum, retard the reaction. The other effect may 

 be explained by the substance taking possession of 

 the surface and displacing the urea from it. This is 

 shown by the so-called " surface-active " substances 

 such as amyl alcohol, bile salts, and saponin. Surface 

 energy is depressed and has a negative temperature- 

 coefficient, and Prof. Bayliss finds that the retardation 

 of reaction is greater at low than at higher tempera- 

 tures. Adsorption of urea by the urease also explains 

 the ratio existing between the concentration of the 

 enzyme and its activity, together with the constancy 

 of the rate of reaction above a certain concentration 

 of the substrate, the latter being due to saturation 

 of the surface. Concentrated solutions of urea greatly 

 retard the action of urease and other enzymes. This 

 is not explained by viscosity or want of water, but is 



