196 



NATURE 



[August 12, ic,oq 



The Borough of Maidstone has issued an excellent and 

 -vvell-illuslrated guide to the local museum and art-gallery, 

 -vvith a history of Chillington Manor House, in which the 

 natural-history collections are preserved. Special attention 

 is devoted in the museum to the local fauna, both recent 

 and extinct, notices of various groups of which are given 

 by "local naturalists and geologists. The illustrations 

 Include photographs of the type-specimen of Cheloiic 

 henstcdi, a local Chalk chelonian now in the British 

 Museum, and of part of the cranium of Odontopteryx 

 toliapica from the London Clay of Sheppey, preserved in 

 1lie Maidstone collection, the only known specimen of that 

 remarkable bird except the type. 



The all-importance of selection to breeders and, in 

 ■perhaps a somewhat smaller degree, to plant-growers 

 (where hybridisation comes more largely into play), is uni- 

 versally admitted, but diflficulties arise in practice when, as 

 is generally the case, it is desired to improve more than a 

 single characteristic of the animal or plant under experi- 

 ment. As an aid in overcoming these difficulties, Messrs. 

 Pearl and Surface, in the July number of the American 

 Naturalist, suggest the adoption of a system of " selection 

 index numbers," the idea of which is to combine in a 

 single numerical expression the values of a series of 

 important characteristics, all of which a breeder may be 

 desirous of iinproving simultaneously. The analytical ex- 

 pression of this idea is discussed in the article, with illus- 

 trations drawn from maize and poultry raising, and it is 

 thus shown that the index numbers fornt a valuable 

 adjunct to the score-card in judging stock. 



Two hotes on the feathers of kalij pheasants (Gennseus) 

 are communicated by Prof. A. Ghigi to vol. xii. of the 

 Rcndiconto of the Royal Academy of Sciences of the 

 Institute of Bologna, the first of these relating to a case 

 of mutation in Gennaeus swinhoei, while the second is 

 devoted to the development of the secondary sexual 

 characters in G. argentaius and certain other birds. In 

 the case of Swinhoe's kalij, certain marked variations 

 from the normal type made their appearance in the feathers 

 •of a bird born in captivity, and as these cannot be 

 attributed to hybridism, they are regarded as an instance 

 ■of true mutation. In the second note the variations from 

 the normal type of colouring and pattern produced in the 

 feathers of the silver-pheasant and its hybrids by 

 accelerated and retarded development are described and 

 figured, and their bearing on the production of secondary 

 sexual characters discussed. 



From among a number of articles on natural history 

 and geological subjects forming the second part of the 

 fourth volume of Aiis der Natur, we select for notice one 

 bv Prof. O. Jaekel on a new " find " of Devonian verte- 

 brates between Cassel and Marburg, which has already 

 yielded some very interesting remains, and is likely to 

 produce many more in the near future. From this de- 

 posit, which is especially rich in armoured " placoderms," 

 remains of no fewer than sixty different species of fish and 

 fish-like vertebrates have been obtained, mostly in a 

 wonderfully fine state of preservation, five or six of these 

 belonging to forms previously known only by small por- 

 tions of the armour. The author gives a restoration of 

 the external form of Coccosteus, based on the new 

 material, and differing very widely from the one in Dr. 

 Smith Woodward's " Catalogue of Fossil Fishes." As 

 now restored, the creature has four paired fins, a low but 

 long dorsal fin, with a gap above the interval between 

 the paired fins, and a somewhat similar ventral fin, con- 

 tinued along part of the long, whip-like tail, this long, 

 NO. 2076, VOL. 81] 



slender tail being hypothetically added from evidence sup- 

 plied by Dr. Traquair. In conclusion, Dr. Jaekel rer 

 marks that the most noteworthy feature in the new 

 deposit is the occurrence of the remains of a number 

 of forms of placoderms in one spot, whereas in other 

 places only a few such are found in association. It 

 indicates, in the author's opinion, a kind of " explosive 

 development." 



We have often been surprised at the curiously un- 

 scientific, but unfortunately very common, use of the term 

 " ovum " by medical writers to designate a human embryo 

 which has developed very far beyond the unicellular con- 

 dition to which alone the term ought to be applied. We 

 believe that a certain section of the medical profession 

 is apt to question the importance of preliminary scientific 

 education, but the 'short time spent by the medical student 

 over his elementary biology would not be wasted even if 

 it did no more than give him some idea of accurate 

 terminology. The immediate occasion for these remarks 

 is afforded by a paper by Maximilian Herzog in a recent 

 number of the American Journal of Anatomy (vol. ix., 

 No. 3), in which the author describes a very young human 

 embryo, closely resembling that known as " Peters' 

 ovum." Our information as to the early stages in the 

 development of man is, from the nature of the case, so 

 extremely meagre that any fresh light on the subject will 

 be welcomed by embryologists. The embryo in question 

 is regarded as representing the earliest stage of normal 

 human development hitherto known, perhaps from one to 

 two weeks after fertilisation. 



The Bulletin of the Liverpool School of Tropical 

 Medicine, of which the first number has just been issued, 

 contains correspondence relating to malaria and mosquito 

 reduction at Isniailia and Helouan. At Ismailia the 

 expense of the anti-malaria measures has averaged 18,000 

 francs per annum. In 1903 malaria cost the Suez Canal 

 Company 38,200 francs ; in 190S this item dropped to 

 16,800 francs. 



We have received the second number of the Eugenics 

 Review (i., No. 2, July), published quarterly by the 

 Eugenics Education Society. The contents include editorial 

 notes and reviews of books, and articles by Sir Francis 

 Galton, Mr. John Russell, Miss A. H. P. Kirby, and 

 others. The review cannot fail to be both interesting and 

 instructive to all those who have the welfare of the race 

 at heart. 



NicoLLE and Adil-Bey in 1902 reported that the in- 

 fective particles of cattle-plague virus would pass through 

 the Chamberland porcelain filter " F, " and their results 

 were confirmed by Yersin. E. H. Ruediger states (Philip- 

 pine Journal of Science, iv., 1909, No. i, p. 37) that he 

 was not able to verify these results, and in a second 

 series of experiments, using four different filter candles, 

 confirms his previous work, no filter candle having been 

 found to allow the cattle-plague virus to pass through. 



It is a usual custom in pharmacological work to state 

 the dosage of drugs as so much per kilogram of body- 

 weight of animal or man, the subject of experiment or 

 treatment. Prof. Benjamin Moore points out in the Bio- 

 chemical Journal (iv., Nos. 5, 6, and 7, July) that this 

 method of stating dosage is inaccurate, the dose of a drug 

 for two individuals of different size, apart from peculiar 

 idiosyncrasies, being proportional, not to their weights, 

 but to their body surfaces, in other words, to the two- 

 thirds powers of their weights. Thus an adult of 150 lb. 

 weight cannot be given fifteen times the dose for an infant 



