194 



NATURE 



[April 24, 1913 



satisfactory from this point of view, and is based on a 

 somewhat extensive collection of valuable data. The 

 note on the spawning of the plaice by the same author, 

 on the other hand, with its accompanying plate, seems 

 to be of only trifling value, and might well have been 

 allowed to rest in the laboratory notebook until further 

 and more conclusive observations could be added. 

 Prof. Meek contributes short papers on lobster cul- 

 ture, on mussel culture, and on the protection of 

 crabs and lobsters, and measurements of certain 

 samples of herrings are also recorded. 



In the current number of The Quarterly Journal of 

 Microscopical Science (vol. lviii., part 4) Mr. G. E. 

 Johnson gives an account of those familiar yet little- 

 known organisms, the nematodes of the common 

 earthworm. Larval nematodes occur abundantly, both 

 encysted in the body-cavity and in an active condition 

 in the nephridia. These are shown to belong to the 

 same species, which the author distinguishes as 

 " Rhabditis pellio, Biitschli, non Schneider." As 

 Schneider's species was described first it is obvious, 

 as the author points out, that a new specific name 

 will be required for the form under discussion, but 

 he refrains from giving this name until Schneider's 

 species shall have been re-examined. Apparently the 

 nematodes do no harm to the earthworm, and they 

 only reach the adult condition in the decaying body 

 of the worm after the latter has died. There is no 

 evidence of another host, but the complete life -history 

 is not yet known. Another paper of interest from the 

 point of view of economic zoology is by Mr. J. David- 

 son, being the first part of an elaborate memoir on 

 the structure and biology of the woolly aphis of the 

 apple-tree, often known as the American blight. Cap- 

 tain Meek contributes a useful discussion on the 

 mechanism of mitosis, from which it appears very 

 evident that, in spite of numerous theories, no satis- 

 factory explanation of the phenomena has yet been 

 arrived at. The only general conclusion that can be 

 drawn at present appears to be " that the mitotic 

 spindle is not a figure formed entirely by the action 

 of forces at its poles." 



The April number of Bedrock (vol. ii., No. 1) offers 

 a varied and interesting bill of fare to its readers, 

 ranging from a study of Japanese colonial methods, 

 by Miss Ellen Churchill Semple, to Prof. H. H. 

 Turner's essay on the nebular hypothesis and its 

 developments. Miss Semple's article affords an in- 

 teresting glimpse of the up-to-date application of scien- 

 tific principles to colonisation as practised by the 

 Japanese. In the island of Formosa the savage 

 aborigines are isolated by means of a wire fence 300 

 miles long, the lowest wire of which is charged with 

 an electric current strong enough to stun or kill 

 anyone trying to climb over or creep under it. The 

 fence is guarded at intervals of 500 yards by block- 

 houses with armed police, one of whose functions is to 

 receive the natives within the pale of civilisation when 

 they are prepared to submit, and thenceforth to edu- 

 cate and look after them generally. Prof. Poulton 

 contributes a very useful account of the latest advances 

 in our knowledge of the phenomena of mimicry, as 

 illustrated by the African Papilioninae. It will be 

 NO. 226g, VOL. 91] 



remembered that the polymorphic females of certain 

 species of this group of butterflies are adapted to 

 mimic various species of Danainae and AcraeinEe in 

 different parts of the continent, and that one and the 

 same female may produce several different forms of 

 mimicking offspring. Prof. Poulton dismisses the 

 suggestion that the different forms of mimicking 

 pattern have arisen by sudden mutation, and brings 

 forward evidence to show that they have been pro- 

 duced gradually by natural selection. At the same 

 time he adduces evidence which suggests that the 

 different patterns may be inherited in Mendelian 

 fashion. The discussion on telepathy as a fact of 

 experience is continued by Sir Oliver Lodge and Sir 

 Ray Lankester, and Mr. McDougall has a very in- 

 teresting article on modern materialism, in which 

 he discusses the question of Vitalism versus Mechan- 

 ism. Considerations of space prevent us from men- 

 tioning other valuable contributions. 



Reprints have been received of two interesting 

 papers dealing with the evolutionary aspects of plant 

 ecology, one by Rev. G. Henslow (" Evolution con- 

 sidered as Bearing upon the Evolution of Plants," 

 Scientia, vol. xiii., 1913, 19 pp.), and the other by 

 Mr. L. Cockayne, F.R.S. ("Observations Concerning 

 Evolution Derived from Ecological Studies in New 

 Zealand," Trans. N.Z. Inst., vol. xliv., 1912, 50 pp., 

 8 plates). The latter is of especial importance from 

 the wealth of observational data which it contains, 

 throwing' light upon various problems in the ecology 

 and biologv of plants in general, and suggesting many 

 others which are open for investigation. It is not pos- 

 sible here to analyse these publications, which will 

 doubtless receive attention in the newly founded 

 Journal of Ecology. It must suffice to say that both 

 authors urge that students of evolution have not paid 

 sufficient attention to the material drawn from the 

 ecological study of vegetation, and that many facts 

 concerning the relation of plants to environment can 

 only be adequately explained on the assumption that 

 characters evoked by stimuli affecting the body-cells 

 are emphatically capable of being inherited. 



Lady Isabel Browne has sent a reprint of "Contri- 

 butions to our Knowledge of the Anatomy of the Cone 

 and Fertile Stem of Equisetum " (Annals of Botany, 

 vol. xxvi.), from which it appears — as so frequently 

 happens — that the re-investigation of the structure of 

 even the most familiar plants, especially those belong- 

 ing to groups which had a much greater development 

 in the past than at the present day, results in the 

 filling-up of various gaps in the knowledge of these 

 groups. The author gives an historical introduction 

 indicating previous work d9ne on this much-investi- 

 gated genus, and after presenting the results of her 

 own thorough examination of the anatomy of the 

 cone and fertile stem of several horsetail species, dis- 

 cusses the general organisation of the cones in the 

 recent and extinct Equisetales. The structure of the 

 cone axis or stem supports the view that the spore- 

 bearing organs (sporangiophores) are whole append- 

 ages and not lobes of a sporophyll or leaf. The 

 collar-like outgrowth (annulus) below the cone in 

 recent horsetails appears to represent a reduced node ; 



