July 5, 1900] 



NA TURE 



239 



Luxor to Wady Haifa. It is known to the natives as " Khuther," 

 and old plants with ripe seed are used as fodder. The dried 

 plant is unusually green, and possesses the aroma of nevr-mown 

 hay. At certain stages of its growth it is highly poisonous to 

 horses, sheep and goats, the poisonous property being most 

 marked in the young plant up to the period of seeding. Owing 

 to the trouble which this plant has given to the military and civil 

 authorities in Egypt, the assistance of the Director of Kew was 

 sought in order that the precise nature of the poison might be 

 ascertained, and, if possible, a remedy found. The matter 

 having been referred to the Scientific Department of the Imperial 

 Institute, Mr. E. A. Floyer, Director of Egyptian Telegraphs, 

 collected some of the material for investigation. 



It was found that when moistened with water and crushed, 

 the leaves of the plant evolved prussic acid in considerable 

 quantity, the amount being greatest in the plant just before and 

 least just after the flowering period. Further investigation has 

 shown that the prussic acid originates with a yellow crystalline 

 glucoside (C.^oHijiNO,,,), which it is proposed to name lotusin. 

 Under the influence of an enzyme, also contained in the plant, 

 lotusin is rapidly hydrolysed, \oxm\x\^ prussic acid, sugar, and a 

 new yellow colouring matter {lotoflai'in). The hydrolysis may 

 be eflfected by dilute acids, but is only very slowly brought 

 about by emulsin and not at all by diastase. The peculiar 

 enzyme, which it is proposed to call lotase, appears to be 

 distinct from the enzymes already known. Its activity is 

 rapidly abolished by contact with alcohol, and it has only a 

 faeble action on amygdalin. Old plants are found to contain 

 lotase but no lotusin. 



The sugar has been proved to be identical with ordinary 

 dextrose. 



Loloflavin, the yellow colouring matter, has the composition 

 expressed by the formula CuHjoOg. It belongs to the class of 

 phenylated pheno-7-pyrones, and isa dihydroxychrysin, isomeric 

 with luteolin, the yellow colouring matter of Reseda luteola, 

 and with fisetin the yellow colouring matter of Rhus cottnus. 



The decomposition which ensues on bringing lotase in contact 

 "ith lotusin, as happens when the plant is crushed with water, 



therefore probably expressed by the following equation : — 



CooHi9NOi„ + 2H,0 = C, 

 Lotusin. 



Hydrocyanic (prussic) acid occurs in small quantity in many 

 plants, and according to Treub and Greshof is often present in 

 the free state. The only glucoside at present definitely known 

 which furnishes this acid is the well-known amygdalin of bitter 

 almonds, which under the influence of the enzyme emulsin, 

 also contained in the almond, breaks up into dextrose, benz- 

 aldehyde and prussic acid. 



Owing to the scientific interest which attaches to this new 

 glucoside, its properties and those of its decomposition products 

 have been very fully studied, and the characteristics of the new 

 enzyme have also been investigated. 



We are much indebted to Mr. Floyer for the great pains he 

 has taken to collect, in Nubia, the necessary material for this 

 investigation, and also to Sir W. T. Thiselton-Dyer for having 

 grown the plant at Kew from seed obtained from Egypt. 



"The Exact Histological Localisation of the Visual Area of 

 the Human Cerebral Cortex." By Joseph Shaw Bolton, B.Sc, 

 M.D., B.S. (Lond.). 



Geological Society, June 6.— J. J. H. Teall, F.R.S., 

 I'resident, in the chair. — Mechanically-formed limestones from 

 Junagadh and other localites, by Dr. J. W. Evans. After 

 • •viewing the conditions under which granular limestones may 



■ accumulated by current- or wind-action, the author proceeds 

 .. describe the limestone of Junagadh, a deposit some 200 feet 

 thick, resembling in hand-specimens the Oolites of this country, 

 though less firmly cemented together. The deposit is situate 

 at a distance of thirty miles from the sea, and contains no large 



'^sils of any kind. Calcareous rocks of similar character are 

 ■scribed from other parts of Kathiawad, Kach, the South- 

 cistern coast of Arabia, and the Persian Gulf— some of these 

 contain unbroken marine shells and other fossils. These beds 

 are included by Dr. H. J. Carter under the name of miliolite, on 

 account of the frequent presence in them of the genus Miliola. 

 The author discusses the origin of these deposits, and comes to 

 the conclusion that the grains were formed in sea-water saturated 

 A ith carbonate of lime: some being deposited by currents in 



uillow water, and others thrown up as a calcareous beach, from 

 Ahich a portion were sifted out by the wind and blown inland 



NO. 1 60 1, VOL. 62] 



'i5"io96 + HCN -I- CsH,20«. 

 Lotoflavin. Prussic acid. De.xtrose. 



to form reolian deposits.— Note on the consolidated reolian sands 

 of Kathiawad, by Frederick Chapman. The name miliolite- 

 formation was originally given by Dr. H. J. Carter to certain 

 granular calcareous deposits occurring on the coast-line between 

 the peninsula of India and the mouth of the Indus. The 

 foraminifera and other organic remains in the rocks must have 

 inhabited moderately shallow to littoral marine areas. The 

 minute granules are worn and polished ; the prev.niling genera of 

 foraminifera are roundish, and would be easily moved by wind ; 

 remains of larger organisms are absent ; and the deposits are 

 false-bedded. All these phenomena are explicable if the 

 deposits represent the accumulation of material derived from 

 littoral calcareous sand of marine origin, mixed with rnineral 

 detritus from adjacent hills.— On Ceylon rocks and graphite, by 

 A. K. Coomara Swamy. Ceylon is surrounded by raised beaches, 

 and has been elevated in recent geological times ; fluviatile 

 deposits also occur : the gems for which Ceyloii is famous are 

 obtained from gravels in the Ratnapura district. With the 

 exception of these recent deposits, the island probably consists 

 entirely of ancient crystalline rocks. Graphite occurs chiefly in 

 branching veins in igneous rocks, which at Ragedara are 

 granulites and pyroxene-granulites. The relations to the matrix 

 are described, and are held to favour the idea of the deposition 

 of the mineral as a sublimation-product (Wallher), or from the 

 decomposition of liquid hydrocarbons (Diersche). Analysis of 

 several of the minerals, including manganhedenbergite, are given ; 

 and a bibliography of the geology of the island is appended. 



Mineralogical Society, June 19.— Prof. N. S. Maskelyne, 

 F.R.S., Past- President, in the chair.— Prof. H. A. Miers pre- 

 sented a communication from Miss Agnes Kelly on conchite, a 

 new form of calcium carbonate. Conchite forms the material 

 of various calcareous secretions in the animal kingdom (more 

 particularly molluscan shells) which have hitherto been referred 

 to aragonite ; it also occurs as the fur in kettles and^ boilers, 

 and in many concretionary deposits, such as those of Karlsbad. 

 In most of its characters it is intermediate between calcite and 

 aragonite ; like calcite it is uniaxial negative, but shows no 

 cleavage or twinning, and has higher indices of refraction ; and 

 like aragonite it is converted into calcite on heating, but the 

 change takes place at a lower temperature. — Mr. G. F. Herbert 

 Smith described a method for the determination of the three 

 principal indices of refraction from observations made in any 

 arbitrary zone. This method is intended for minerals of low 

 symmetry of which the indices are higher than those of any 

 liquid. Observations are made of the deviations corresponding 

 to different angles of incidence on both faces of a prism, and 

 curves connecting the indices and the angles of orientation are 

 plotted out. As in the method of total reflection, three of the 

 critical values give the principal indices. — Mr. H. L. Bowman 

 described the occurrence of monazite at Tintagel, and gave a 

 detailed account of the crystallographic characters of the asso- 

 ciated minerals, albite, quartz,' rutile, pyrites and calcite.— 

 Dr J. W. Evans discussed the alteration of pyrites by under- 

 ground water, a question which had arisen in connection with 

 the erection of a dam in Mysore. From his experiments the 

 author concludes that, provided the water contain a sufficient 

 amount of carbonate of lime to neutralise the sulphuric acid 

 resulting from the oxidation of the pyrites, exact pseudomorphs 

 of limonite after pyrites are formed ; and as these occupy 

 practically the same volume as the original pyrites, the rock 

 suffers little disintegration by the action of the water. — 

 Petrological notes by Mr. G. T. Prior dealt with the so-called 

 "cancrinite-regyrine-syenite" of Elfdalen, which he refers to 

 sussexite at the basic end of the grorudite-tinguaite series 

 of Brogger ; with a riebeckite-regyrine-tinguaite (so-called 

 " proterobase ") from the Rupbachthal ; and with melilite- 

 basalts from Madagascar and Siam.— Mr. L. Fletcher discussed 

 the quantitative determination of the action of hydrochloric 

 acid and of soda-solution on the enstatite and felspar of the 

 Mount Zomba meteorite. 



Cambridge. 



Philosophical Society, May 21.— Mr. J. Larmor, President, 

 in the chair.— On a certain diophantine inequality, by Major 

 MacMahon, R.A., F.R.S.— On rational space curves of the 

 fourth order, by Mr. Richmond.— On the reduction of quadrics, 

 by Mr. Bromwich.— Experiments upon the rise of temperature of 

 fabrics when moistened, by Dr. L.Cobbett. Dr. Cobbett showed 

 that if expired air is breathed through several layers of dried filter 

 paper wrapped round the bulb of a thermometer, a temperature 



