January 15, 1903] 



NA TURE 



2 53 



Cyanotis and Panicum are used. Other sources of nourishment 

 are the leaves of Amarantus, Rivea and Leptadenia. A system- 

 atic enumeration of the species of Calamus and Dcemonorops, 

 by Mr. O. Beccari, is based mostly on plants growing in the 

 Malayan Peninsula and the adjacent islands, and only a few 

 species belong to India or Ceylon. 



An addition to our knowledge of semiparasitic plants is made 

 by Mr. S. Kusano, who contributes the result of his studies on 

 Buckkya quadriala, a genus of the Santalaceiv, to the Journal of 

 the College of Science, Tokio. The plant was found growing 

 naturally on several hosts, some Dicotyledons and some Gymno- 

 sperms, but a decided preference and better development was 

 ■displayed on the roots of Abies and Cryptomeria. The haustoria 

 .arise laterally in the young stage, but eventually appear to 

 originate from the apex, or in reality in close proximity to the 

 apex. A feature which has only been suggested for allied 

 genera, e.g. secondary growth due to cambium, is in Buckleya 

 so marked that the contour of the vascular strand is entirely 

 changed and definite medullary layers become differentiated. 

 Since the cambiums are adjacent and develop tissue to the same 

 degree, the sucker keeps pace with the growth of the host root. 



A BRIEF critical review of the theories relating to plant 

 evolution, more particularly the origin of new forms, is offered 

 by Prof. Schwendener in a recent number of the Naturwissen- 

 schaftluhe Wochenschrift. The article touches upon the origin 

 of species by natural selection, the variations developed as 

 special adaptations due to environment, the mutation theory and 

 incidentally the production of hybrids. The arduous experi- 

 mental work of De Vries and the possibilities of mutation or 

 heterogenesis are acknowledged and accepted, but the opinion 

 is expressed that new forms have not all originated after the same 

 manner and that the direct action of external conditions has un- 

 doubtedly played an important part in the production of new and 

 the modification of acquired characters. Prof. Schwendener is in 

 accord with Darwin's theory of selection so far as it is limited to 

 the origin of cultivated races of plants and to the breeding of 

 domesticated animals, but does not believe in its application 

 under natural conditions. This view, which coincides with the 

 expressions of other eminent German botanists, naturally tends 

 to diminish the importance previously attached to the theory of 

 natural selection, but the writer pays just tribute to the value of 

 Darwin's work, " whose service it was," he says, " to set on a 

 new foundation the doctrine of descent, and after a struggle 

 which was victoriously pursued to establish the idea permanently 

 in biological science." 



Prof. F. Frech contributes to theZeilsilirifl der Gesellschaft 

 fiir Erdkunde (Nos. 7 and 8) a series of studies of the climates 

 of past geological times. He accepts the views of Arrhenius 

 with regard to the effect of variations in the amount of carbonic 

 acid gas in the atmosphere, and considers the changes in the 

 distribution of land and sea as the factor of next importance. 

 The review of the geological evidence is interesting and im- 

 portant, but the author hardly gives sufficient prominence to 

 physical aspects of the question, especially the effect of changes 

 of temperature distribution on the atmospheric circulation and 

 the influence of oceanic currents upon climate. The maps of 

 continents and seas at the end of the Carboniferous period and 

 of Europe during the Glacial period are valuable. 



Two more volumes of the excellent Scientia series of scientific 

 monographs published in Paris by M. C. Naud have reached us, 

 viz., " Le leucocyte et ses granulations," by Dr. C. Levaditi, and 

 " Les phenomenes des metamorphoses internes," by Dr. J. 

 Anglas. The volumes fully maintain the high character of 

 preceding books in this series. 



NO. 1733, VOL. 67] 



The Orient Steam Navigation Company announce the com- 

 mencement of their 1903 season of pleasure cruises. No. 1 

 cruise, starting February 26, is to the Riviera and on to 

 Palestine, calling en route at Tangier, Palnu, Sicily, Crete 

 and Cyprus, returning home by way of Alexandria, Naples, 

 Algiers and Gibraltar. The second cruise, leaving London 

 March 14, is to Tangier, MiUga, Nice, Palermo, Crete, 

 Smyrna and Constantinople, visiting on the return voyage the 

 Pitieas (for Athens), Nauplia, Katakolo (for Olympia), Naples, 

 Algiers and Gibraltar. 



The reversible transformation of ammonium thiocyanate into 

 thiourea has recently been investigated on a large scale by 

 Reynolds and Werner, who give an account of their experi- 

 ments in ihe Journal of the Chemical Society. At temperatures 

 from i7o'-l8o° C, the fused product obtained by heating 

 either ammonium thiocyanate or thiourea for a sufficient time 

 consists of 75 per cent, of the former and 25 per cent, of the 

 latter. It is believed by the authors that the reversible change 

 is partly conditioned by the greater stability at this temperature 

 of a complex compound consisting of three molecules of thio- 

 cyanate and one molecule of thiourea. 



The first number of vol. i. of the Biochemisches Centralblatt 

 has just been published. In twenty-eight pages it gives 

 abstracts of some sixty papers dealing with subjects which 

 belong essentially to the borderland of chemistry and medicine. 

 It is pleasing to note that a considerable number of these are 

 auto-abstracts, for this method of summarising is the only one 

 which ensures that the really essential points in the various 

 investigations are brought forward. The issue also contains a 

 short summary by N. Zuntz of the recent work which has been 

 carried out in America on such an elaborate scale by Atwater 

 and his co-workers on the metabolism of the animal body. To 

 physiological chemists, the Centralblatt will no doubt prove of 

 considerable value, serving, as it is intended to do, for the 

 collection of reports on all published medico-chemical investiga- 

 tions. 



The much-discussed question of the relationship between the 

 red and yellow oxides of mercury may now be regarded as 

 definitely decided. The experiments which lead to this con 

 elusion form the subject of a paper by K. Schick, published in 

 the last number of the Zeilschrift fiir physikalischc Chemie. 

 The results indicate that Ostwald's view that the difference 

 between the two oxides is merely due to a difference in the size 

 of the particles is the correct one, and that the older hypothesis, 

 according to which the oxides are isomeric, is no longer tenable. 

 Determinations of the solubility of the pure oxides in pure 

 water at 25° C. show that they .have practically the same 

 solubility. Of the yellow oxide, one part dissolves in 19,300 

 parts of water, and one part of the red oxide in 19,500 parts. 

 Such a small difference is due, in all probability, to the difference 

 in the size of the grains. 



The current number of the Zeitschrift fiir physikalische 

 Chemie contains an interesting paper by Dr. M. VVildermann 

 on chemical dynamics and statics under the influence of light. 

 The author's object has been to ascertain, if possible, the law. 

 which regulate the velocity of chemical change and the condition 

 of chemical equilibrium, when such change is conditioned by the 

 introduction of light energy into the system. In other words, it 

 was proposed to investigate whether the velocity is proportional 

 to the amount of light absorbed in unit time independent of the 

 concentrations of the reacting bodies. The special chemical 

 change which has been studied is the union of carbon monoxide 

 and chlorine, a reaction which takes place only under the in- 

 fluence of light. A theoretical discussion of the experimental 

 results leads the author to conclude that the velocity of a 

 chemical reaction which is brought about (or influenced) by 



