February 26, 1920] 



NATURE 



707 



with certainty that a particular type of implement 

 was present. Mr. Reid Moir's collection appeared to 

 him to present all the characteristics which one would 

 expect to find in a group of implements belonging to 

 the Le Moustier culture. 



Mr. Kennard said that palaeontologists were firmly 

 convinced that the Boulder Clay was of late occur- 

 rence. An examination of a continuous series of 

 examples of the fauna exhibited no traces of the 

 variation between warm and cold types, which would 

 have been expected to occur if the theory of alter- 

 nating warm and cold periods were correct. Fauna 

 of the cold period were always last in the series. 

 Mr. H. Bury said that the evidence brought forward 

 bv Mr. Reid Moir made it necessary to raise the 

 question whether Chalky Boulder Clay was always, 

 and wherever it occurred, of the same age. The 

 evidence from Hoxne was diametrically opposed to 

 Mr. Reid Moir's results, and this, together with the 

 doubts which had been expressed as to the character 

 of the evidence obtained from Hoxne, made it desir- 

 able that the borings on that site should be repeated. 



RECENT ENGLISH MARINE BIOLOGY. 



RECENT English papers on marine biological 

 research include one by Dr. E. C. Jee on the 

 hydrography of the English Channel during the years 

 1904-17. This forms part i. of the Fisheries Inves- 

 tigation Series III., the publication of which is now 

 resumed by the Board of Agriculture and Fisheries. 

 Periodicities in the physical properties of the Channel 

 water are discussed, and correlations between these 

 and the pilchard fisheries are apparently established. 

 A most interesting " Contribution to the Quantitative 

 Study of Plankton " is published by Dr. E. J. Allen 

 in part i., vol. xii., of the Journal of the Marine Bio- 

 logical Association. 



Plankton investigations, in so far as they have been 

 quantitative, have been a series of approximations to 

 a complete determination of the number of organisms 

 of all kinds contained in a unit volume of sea-water. 

 Hensen's original method consisted in the use of a 

 net made of fine-meshed silk cloth which was lowered 

 in the sea and hauled to the surface. Exf>eriment and 

 calculation gave a coefficient for each net, from which 

 the area of cross-section of the column of water fil- 

 tered could be approximately determined. It has been 

 found latterly that the greater number of microscopic 

 organisms in the water escaped through the meshes 

 of the cloth, and more refined filtering methods were 

 introduced by Lohmann. 



Finally, it was thought that by centrifuging small 

 quantities of water a complete enumeration of the 

 organisms present might become possible, and this 

 method did, indeed, largely increase the numbers in- 

 habiting unit volume of sea-water. Why it should not 

 enable the investigator to determine all is not easy to 

 see, but it certainly under-estimates them, as Dr. 

 Allen's results show. In his experiments small quan- 

 tities of water (lo c.c.) were centrifuged and the con- 

 tained organisms counted. From four such trials a 

 mean of 14-45 PC ^-c. (or 14,450 organisms per litre) 

 was obtained. The same water sample was then 

 examined by inoculating i c.c. in a sterilised sea- 

 water containing the culture solutions used by Allen 

 and Nelson for the study of marine diatoms. The 

 inoculated medium so prepared was then distributed 

 into seventy small flasks, each containing about 20 c.c. 

 of the liquid, and the latter were allowed to stand for 

 several weeks. The colonies (mainly Diatoms and 

 Flagellates) growing in the flasks were then identi- 

 fied and counted, giving an estimated number of at 

 least 464 organisms per c.c. (or 464,000 per litre). 



NO. 2626, VOL. 104] 



Even then it is evident that the result is an under- 

 estimate of the actual population of the water sample, 

 for the medium is apparently selective, and organisms 

 that app)eared in the centrifuged samples did not grow 

 (and were therefore unrecorded) in the cultures. Bac- 

 teria did grow, but were not identified and esti- 

 mated. The result is therefore another, and closer, 

 approximation to a biological value which is of extra- 

 ordinary interest. J. J. 



THE RED COLOURING MATTER OF 

 PLANT GALLS. 



TOURING recent years our knowledge concerning 

 -'-^ plant colouring matters has rapidly increased, 

 and quite a large number of pigments have been sub- 

 jected to careful and full investigation. A further 

 interesting contribution to our knowledge in this field 

 of research is contained in a recent paper by Dr. M. 

 Nierenstein, in which he deals with the colouring 

 matter of the "red-pea gall" (Trans. Chem. Soc, 

 19 19, cxv., pp. 1328-32). The galls that were 

 examined occur on the leaves of various British oak- 

 trees when galled by Dryophanta divisa, Adler. 



It has been generally assumed that the red colouring 

 matters of these and similar galls belonged to the 

 anthocvan class, and one of the objects of the in- 

 vestigation was to ascertain whether the anthocyan 

 assumed to be present was related to quercetin. By 

 this means it was hoped to obtain some light upon 

 the relationship between the products present in the 

 normal plant and those pathologically produced as 

 the result of the formation of the galls. 



The investigation resulted in the isolation of a red 

 pigment, to which the name "dryophantin " has been 

 given. Dr. Nierenstein concludes that this colouring 

 matter is not an anthocyan, but a diglucoside of pur- 

 purogallin (the first derivative of purpurogallin to be 

 found in Nature), and that, like gallotannin, it is of 

 pathologic origin. He is of the opinion that the 

 other so-called anthocyans obtained from plant-galls 

 are in all probability not anthocyan colours at all, 

 but related to "dryophantin." In view of this 

 he proposes to classify these red pigments under the 

 class-name "gallorubrones." 



This paper is of considerable interest, particularly 

 if further investigation confirms the presence of pur- 

 purogallin derivatives as regular constituents of these 

 and other red galls. In respect of the conclusion 

 implied as to the absence of pigments of the anthocyan 

 group, the present paper is not sufficient evidence of 

 stich absence, for the process whereby the colouring 

 matter has been isolated is such that there is a very 

 considerable doubt whether many anthocyan pigments 

 would survive the treatment. 



IONS AND lONISATION. 



THE Faraday Society, though a small body, is very 

 active. One of the most useful features of its 

 activity is the holding of general discussions on 

 matters of scientific and technical interest, and the 

 publication of these discussions in its Transactions. 

 "The Present Position of the Theory of lonisation in 

 Solution " was the subject of a discussion held on 

 January 21, 1919, and the report is now issued in the 

 form of a separate reprint (pp. 178, Faraday Society, 

 10 Essex Street, Strand, W.C.2, price 12s. 6d.), thus 

 making it available to a larger public than the 

 members of the society. 



The discussion was opened by Dr. Senter, who 

 brieflv reviewed the position with regard to such out- 

 standing problems as the hydration of ions, the devia- 

 tion of strong electrolytes from the mass-action law, 



