October 31, 1907] 



NA TURE 



669 



of the winged adults. At the conclusion of the article 

 special attention is directed to the origin of these 

 dimorphic phases, which include a larger and a smaller 

 form ; diagrammatic illustrations being given of the various 

 theories proposed. According to the author's view, 

 trimorphic nym.phs are developed, from which are pro- 

 duced what he terms the a form, ;8 form, and 7 form, 

 which in turn respectively give rise to the parthcnogenetic 

 gcneriitioii, to males, and to females. 



To the July issue of the Proceedings of the Philadelphia 

 Academy, Mr. E. G. Conklin contributes a paper on the 

 embryology of the gastropod Fulgur, from the point of 

 view of the influence of the yolk on development. The 

 eggs of this genus are remarkable for their large size, 

 the bulk being almost wholly due to the quantity of yolk ; 

 and one of the problems to which special attention was 

 devoted is the effect of large or small yolks on the develop- 

 ment of the organs of the embryo. For the author's 

 conclusions our readers must be referred to the original 

 paper ; but it may be mentioned that after a certain stage 

 the elements of the Fulgur yoke cleave irregularly, a 

 feature which may foreshadow the " meroblastic " eggs 

 of birds and reptiles, in which only a portion of the yolk 

 undergoes cleavage. 



We have received copies of a circular issued by the 

 Vigilance Committee of the Fur and Skin Trade Section 

 of the London Chamber of Commerce directed against 

 the alleged practice of certain retailers in wrongly mark- 

 ing, naming, and advertising furs for sale, in violation 

 of the Act of Parliament against " false trade descrip- 

 tions." The action taken by the committee has already 

 led to satisfactory results, but there appears reason to 

 believe that the illegal practice still continues. Among 

 the scheduled items are musquash and nutria (coypu) fur, 

 sold, " when pulled and dyed," as seal; and nutria, when 

 " pulled natural," sold as beaver. Dyed rabbit fur sold 

 as sable, white rabbit as ermine, and dyed white rabbit 

 as chinchilla, also appear in the list. It is added that 

 purchasers who may have any doubt as to whether furs 

 sold to them are correctly described can obtain expert 

 opinion, free of charge, by forwarding the articles to the 

 offices of the London Chamber of Commerce, Oxford 

 Court, Fleet Street, E.C. 



In the introduction to his report on the diatoms collected 

 in the Pacific Ocean on the voyages during the years 

 i8q8 to 1904 of the steamer AlhaUoss, belonging to the 

 United States Bureau of Fisheries, Dr. A. Mann claims 

 that, as owing to their minuteness diatoms can be trans- 

 ported by slow currents or surface drifts, a tabulation of 

 the species found at different stations would provide useful 

 data for determining the direction and extent of ocean 

 currents. He also quotes several instances to show how 

 different species are confined to, and therefore typical of, 

 distinct localities. The systematic enumeration contains a 

 careful digest and sifting of previous nomenclature. The 

 genera Navicula, Biddulphia, and Coscinodiscus are richest 

 in species, and also provide the larger number of new 

 species. The report is published as vol. x., part v., of the 

 Contributions from the United States National Herbarium. 



We have received the annual report of the medical 

 officer of health (Dr. Seaton) of the administrative county 

 of Surrey for 1906. The prevalence of enteric or typhoid 

 fever in the administrative county is the subject of a 

 special report. The incidence of 2093 cases occurring 

 during the last twelve years has been reviewed, and the 

 opinion is expressed that it is doubtful whether even 

 10 per cent, of the cases can be attributed to the drinking 



of a polluted or infected water supply, and there seems to 

 be no evident relation between the rainfall, and consequent 

 floods, to typhoid prevalence. Dr. Seaton believes that 

 polluted and infected foods are a much more frequent 

 source of typhoid illness than is even now generally sup- 

 posed. He also refers to the occurrence of cases which 

 it is impossible to connect with any other case, and 

 suggests the possibility of new origin (i.e. apart from 

 human infections) through bacilli other than those which 

 are regarded as the invariable specific causes of typhoid. 

 With regard to this, it may be mentioned that I'ecent 

 German researches have shown that patients may harbour 

 the typhoid bacillus for months after they have recovered 

 from an attack, and that even well persons may occasion- 

 ally be the hosts of the organism ; it seems hardly 

 necessary, therefore, to suggest a de novo origin. 



Under the title of " The Tuna as a Food for Man," 

 Mr. R. F. Hare and Mr. D. Griffith have provided in 

 Bulletin No. 64 of the Agricultural College, New Mexico, 

 an illustrated account of the varieties of fruit — commonly 

 called prickly pear — grown to a considerable extent in 

 Mexico. The fruits described are species of Opuntia ; they 

 have a thin skin more or less covered w-ith spicules, under 

 which is a rind enclosing the pulp and embedded seeds. 

 The pulp alone is generally eaten, but sometimes part of 

 the rind is included. The fruit is relished by the peons 

 and poorer classes, and is harvested for shipment. There 

 is also a local manufacture of products of the nature of 

 honey, sugar-paste, and toffee. 



The Quarterly Journal of the Liverpool Institute of 

 Commercial Research in the Tropics, vol. ii.. No. 5, con- 

 tains excellent illustrations of some African fibrous plants 

 from photographs by Mr. J. A. Alexander, formerly of 

 Portuguese East Africa. Dr. E. Drabble furnishes notes 

 on the synonymy, morphology, and fibres of leaves of 

 Sanscvicria guineensis and .igavc rigida, also on the seeds 

 of Myristica angolensis and fruits of Lophira alata. From 

 the latter the natives of West Africa obtain a cooking oil, 

 and the fat of Myristica is suitable for soap-making. Dr. 

 D. Spence contributes articles on the analyses of latex and 

 rubbers, the most important being a discussion of the 

 methods of analysing raw rubbers. 



A SECOND hundred of the leaflets published by the Board 

 of Agriculture for free distribution has been completed. 

 They deal with farm and garden crops, insects and fungal 

 pests, and the breeding and management of farm animals. 

 Among recent issues are two containing information on 

 the winter rot of potatoes caused by the fungus Neciria 

 solani, and the black rot of cabbage attributed to the 

 bacterium Pseudomonas canipcstris. The Nectria appears 

 on stored potatoes, forming white, and later pink, patches, 

 from which arise crops of spores that spread the disease 

 and reduce the tubers to a foetid mass. The ascosporcs 

 developed in the following season can infect growing 

 crops. The cabbage rot is readily distinguished by the 

 black appearance of the vascular bundles along which the 

 bacteria travel. The Sycamore leaf-blotch, caused by 

 species of Rhytisma, so familiar by reason of the black 

 patches produced, is described in another leaflet. An 

 account of the coltsfoot, Tnssilago farfara, and a note on 

 the Fertilisers and Feeding Stuffs Act, 1906, have also 

 been published. 



The King has instituted a now medal for bravery in 

 mines. The Royal Warrant states that the King is 

 desirous of distinguishing by some mark of Royal favour 

 the many heroic acts performed by miners and quarrymen 

 who endanger their own lives in endeavouring to save the 



NO. 1983, VOL. 76] 



