240 



NATURE 



[July 5, 1888 



•munication of April 16, nothing was questioned except the 

 ■novelty of M. Jensen's theorem, which does not differ essen- 

 tially from that of Kummer, as modified and completed by 

 Dini in 1867. — On the hydrochlorates of trichloride of antimony, 

 •of trichloride of bismuth, and of pentachloride of antimony, by 

 M. Engel. The researches here described fully confirm the 

 existence of these bodies, which are described as well-defined 

 salts that may be easily isolated. Like all the other hydrochlorates 

 •of chloride hitherto prepared, they all contain water of crystal- 

 lization, and there are in each case at least two molecules of 

 water for each molecule of hydrochloric acid fixed by the chloride. 

 — On the reproduction of phenacite and the emerald, by MM. P. 

 Hautefeuille and A. Perrey. The conditions are described under 

 which the authors have effected the synthesis of two substances 

 whose properties are identical with those of natural phenacite 

 and the emerald. The analysis of the artificial emerald yielded 

 -silica 677, alumina 19 '6, and glucine 13 '4, which are nearer 

 to the calculated proportions than those given for the compo- 

 sition of most natural emeralds. The analyzed crystals, whose 

 density was 2*67, were colourless ; but greenish-yellow and 

 green crystals were easily obtained — the former by the oxide of 

 iron, the latter by the oxide of chromium. 



Berlin. 

 Physiological Society, June 8. — Prof, du Bois-Reymond, 

 President, in the chair. — Prof. Kossel spoke on a new consti- 

 tuent of tea. Inasmuch as the presence of caffein in tea does 

 not suffice to explain its physiological action, he had examined 

 it for other bases, and found in the leaves of tea, in addition to 

 adenin, a new well-characterized base whose composition is 

 C 7 H 8 N 4 2 , to which he has given the name of theophyllin. 

 Theobromin and paraxanthin have the same chemical compo- 

 sition as theophyllin, but the latter differs from the former by a 

 series of well-marked chemical reactions. One question of 

 special interest was as to the constitution of the new base, which 

 belongs to that class of substances known as the xanthin-bodies. 

 Fischer has shown that xanthin yields alloxan and urea when 

 oxidized ; and, similarly, it is known that theobromin is di- 

 methylxanthin, yielding, by oxidation, methylalloxan and 

 methylurea ; as also that caffein is trimethylxanthin, yielding, 

 by oxidation, dimethylalloxan and monomethylurea. The 

 question hence arose as to the constitution of the new base, 

 which, since it is isomeric with theobromin, is also presumably 

 a dimethylxanthin. Since the speaker was in possession of so 

 limited a quantity of the substance that he could not proceed 

 to oxidize it, he proceeded by a different method, and intro- 

 duced a methyl group into the molecule of theophyllin : on 

 performing this experiment he obtained caffein, from which it 

 must be concluded that theophyllin contains one methyl 

 group united to a residue of urea, and one to a residue of 

 alloxan, and has therefore a constitution identical with that 

 of theobromin. It still remains to investigate the physio- 

 logical action of the new base. — Dr. Will spoke on the 

 alkaloids of the Solanaceae, of which at present only atropin, 

 hyoscyamin, and hyoscin are known as distinct substances with 

 reference to their mydriatic action. The first two of the above 

 are of special interest, as possessing the same chemical compo- 

 sition (C 17 H 23 N0 3 ), but differing as regards their melting-point, 

 the salts which they form with gold, and their specific rotatory 

 powers. It had been noticed long ago that sometimes much 

 atropin and but little hyoscyamin, and, vice versd, much hyos- 

 cyamin and but little atropin, is obtained from the roots of 

 Belladonna. This difference in the relative amounts of the two 

 substances obtained was noticed when portions of the same 

 sample of roots were treated in the same way ; as the result of 

 which the chemical factory of Schering had requested the 

 speaker to investigate the cause of this difference in the relative 

 amounts of the several products. The first fact which he deter- 

 mined was, that when hyoscyamin is heated to 109 ° C. — that is to 

 say, to a temperature slightly above its melting-point — it changes 

 into atropin. This is, however, of no significance in the pre- 

 paration of the alkaloids, as carried on in a factory, inasmuch 

 as no such temperatures are employed. Dr. Will further found 

 that, when a few drops of alkali are added to a solution of hyos- 

 cyamin which posse^ses strong rotatory powers, in a few hours 

 the rotatory power is lost, and the solution no longer contains 

 hyoscyamin, but atropin. According to this, during the extrac- 

 tion of Belladonna roots in the factory, the amount of hyoscya- 

 min which may have become converted into atropin is dependent 

 upon the time of action and the concentration of the alkaline 

 solution employed in the process : by treatment with alkali, tl e 



whole of the hyoscyamin can always be converted into atropin 

 The fact that, by the extraction of the roots of Hyoscyamus, onl; 

 hyoscyamin and no atropin is obtained, was explained by th< 

 speaker as being due to the employment of ammonia in thi 

 process, which has only a feeble power of converting the on< 

 alkaloid into the other. The speaker intends to employ thi: 

 conversion of hyoscyamin into atropin, which is measurable b] 

 means of change in rotatory power, to the determination of th( 

 combining affinities of the alkalies. Dr. Will is inclined tr. 

 believe that relations similar to the above exist in the case o 

 quinine and cinchonine, which are also obtained in varying rela 

 tive amounts from the bark. — Dr. Koenig gave an account o 

 fome experiments, undertaken at his suggestion by Isaacksen. 

 with a view to testing Holmgren's statement that very smal 

 coloured dots can only be seen as one of the primary colours of 

 the Young-Helmholtz theory — namely, red, green, or violet. 

 This statement was not, however, confirmed when the necessan 

 precautions were taken, and it was found that small dots of an; 

 colour, even yellow and blue, were perceived as possessing thei 

 own objective colour ; this had also been observed by Hering 

 Isaacksen had, further, investigated the power which the ey 

 possesses of distinguishing between minute dot-like light 

 which are so small that their image on the retina only falls oi 

 one cone, and found that it was as fully developed as for th 

 colours of large surfaces. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED 



Chemical Problems : Grabfield and Burns (Heath, Boston). — The Mov< 

 ments of Respiration and their Innervation in the Rabbit: Dr. M. Mnrcl 

 wald, translated (Blackie). — Natural History and Epidemiology of Cholera 

 Sir J. Fayrer (Churchill). — The Photographer's Note-book and Index : Sir! 

 Salomons (Marion). — Short Lectures to Electrical Artisans: J. A. Fleming 

 second edition (Spon). — Whence comes Man ; From Nature or from God ': 

 A. J. Bell (Isbister). — Challenger Expedition Report, vols, xxiii., xxiv. 

 Parts, and xxv., Zoology (Eyre and Spottiswoode). — Annual Report of tht 

 Geological and Natural History Survey of Canada, vol. ii. 1886 (Dawsoi 

 Montreal). — Another World, or the Fourth Dimension : A. T. Schofiel I 

 (Sonnenschein). — Changes of Level of the Great Lakes: J. K. Gilbe: 

 (Washington). — The Construction and Maintenance of School Infirmaries an 

 Sanatoria (Churchill). — Electricity versus Gas: J. Stent (Sonnenschein).- j 

 Annalen der Physik und Chemie, 1888, No. 8a (Leipzig). 



CONTENTS. pag 



The Decadence of the Chemical Profession in 



Government Opinion 21 



The Land and Fresh-water Mollusca of India ... 21 



Recent Mathematical Books 21 



The Botany of the Afghan Delimitation Commis- 

 sion 21 



Our Book Shelf :— 



Wrightson : " The Principles of Agricultural Practice 



as an Instructional Subject" 22 



Edwards-Moss : " A Season in Sutherland " .... 22 

 Letters to the Editor : — 



"Sky-coloured Clouds" at Night.— R. T. Omond . 22 



Micromillimetre. — Frank Crisp 22 



A Prognostic of Thunder. — B. Woodd-Smith . . . 22 



Parasites of the Hessian Fly.— F. E. S 22 



Fact and Fiction. — Harry Napier Draper .... 22 

 The Nephridia of Earthworms. — Frank E. Beddard 22 



The " Avocet " Rock. {With a Chart.) 22 



Magnetic Strains. {Illustrated.) By Shelford Bid- 

 well, F.R.S 22 



A Meteorologist at the Royal Academy. By Hon. 



Ralph Abercromby 22 



The Oxford University Observatory 22 



Notes 22 



Our Astronomical Column : — 



American Observatories 23 



Minor Planets 23 



The Rings of Saturn 23 



Astronomical Phenomena for the Week 1888 



July 8-14 2" 



Electrical Notes 23 



The Micro-organisms of Air and Water. {Illus- 

 trated.) By Dr. Percy F. Frankland 2' : 



The Opening of the Marine Biological Laboratory 



at Plymouth is 



University and Educational Intelligence 



Scientific Serials 



Societies and Academies 



Books, Pamphlets, and Serials Received 



