i8o 



NATURE 



[April 7, 192 1 



In a short note on the fresh-water isopods known 

 as Aselhts aquaticus {Ann. Mag. Nai. Hist., ser. 9, 

 vol. v., 1920) Prof. C. Chilton directs the attention 

 of English naturalists to a recent paper by Dr. E. G. 

 Racovitza, who has shown that under the name 

 aquaticiis two distinct species have been included. 

 This name is retained for the commoner species which 

 has been fully described and figured ; the other species 

 has been named meridianiis , and Prof. Chilton 

 records examples from Tunbridge Wells. For the 

 differences between the species the reader is referred 

 to Prof. Chilton's note or to Dr. Racovitza's paper 

 in Arch. Zoo]. Exper., vol. Iviii., 1919. 



Some years ago the authorities of the American 

 Museum of Natural History founded a journal for 

 the purpose of arousing public interest in the work of 

 the museum. Brightly written by members of the 

 museum staff, and marvellously illustrated, that 

 journal has earned for itself an honoured place all 

 over the world. We might well follow the lead 

 America has set us in this matter. The latest issue 

 (vol. XX., No. 5), among other good things, contains 

 a most interesting article on the unicorn and its horn 

 by the director of the museum, Dr. Frederic A. Lucas, 

 and another, no whit less readable, by Dr. W. D. 

 Matthew on Canadian dinosaurs, while Mr. Malcolm 

 'Anderson contributes a most instructive account of 

 North China in winter. 



In his presidential address (printed in Science for 

 January 21 last) before the Zoological Section of the 

 American Association for the Advancement of Science 

 at its Chicago meeting Prof. W. M.Wheeler discussed 

 the subject of organisation in research as it appears 

 to a biologist, and pointed out some of the dangers 

 attending post-war efforts in this direction. He men- 

 tioned the array of instincts, emotions, and interests 

 on which the activities of the investigator depend and 

 the great diversity of mental aptitude which neces- 

 sarily accompanies the genius for different types of 

 research. Prof. Wheeler claims that any organisation 

 dealing with research should refrain carefully from 

 interfering in any degree with the free expression of 

 the individual's exceptional aptitudes in his own way. 

 In these days when the amateur in scientific research 

 is passing we need to beware of fettering in any way 

 by Government or other interference the activities of 

 the professional scientific man. 



A HUMAN embryo obtained by Dr. Vernon Favell on 

 the fourteenth day after the commencement of the 

 missed menstrual period, and described by Prof. Bryce 

 at a recent meeting of the Anatomical Society of 

 Great Britain and Ireland, is of outstanding interest 

 in that it presents a human stage theoretically 

 essential, but not actually seen hitherto. The stage 

 represented is that in which the amnio-embryonal 

 rudiment is solid and connected to the blastocyst wall 

 by a cellular stalk. The specimen consists of a rela- 

 tively large blastocyst around which moderately exten- 

 sive areas of plasmodi-trophoblast can be seen. 

 Within the cavity are many scattered amoeboid cells, 

 the. forerunners of the extra-embryonic mesoderm. 

 The yolk-sac vesicle is relatively small, and a large, 

 NO. 2684, VOL. 107] 



somewhat scattered group of cells lies between it and 

 the amnio-embryonal rudiment. The latter consists of 

 an undifferentiated cell mass with spaces suggestive 

 of a process of vacuolisation and connected to the 

 blastocyst wall at one point by a band of cells. The 

 majority of early human embryos previously described 

 have been of necessity in a more or less pathological 

 condition, and the appearances seen cannot be re- 

 garded as strictly normal. Prof. Bryce makes no 

 claim that his embryo is exceptional in this respect. 

 He interprets the specimen as one in w'hich the tropho- 

 blast vesicle has continued to grow, while the em- 

 bryonic rudiment has lagged behind or ceased to 

 develop, but has been preserved in an early phase of 

 its differentiation. Further study of the specimen 

 will undoubtedly furnish valuable information, and its 

 detailed description is awaited with considerable 

 interest. 



The final report of the Grain Pests (War) Com- 

 mittee has been drawn up by Prof. W. A. Herdman 

 and was issued during February of the present year. 

 The Committee was appointed by the Council of the 

 Royal Society in June, 1916, as the result of corre- 

 spondence with the Board of Agriculture, in which the 

 latter requested the Royal Society to initiate investiga- 

 tions " in relation to the damage done to grain by 

 insects." The report gives a concise summary of the 

 conclusions arrived at as the result of the various 

 lines of research carried out. It emphasises the 

 serious importance to the Empire of the elimination 

 of grain pests and the necessity for bringing into being 

 a permanent body capable of dealing with all organisms 

 causing destruction to grain and other stored products. 

 It is hoped that the Department ot Scientific and In- 

 dustrial Research will see its way to make\an annual 

 grant of money in order to provide the sajlaries and 

 equipment of two or three officers specially selected 

 for carrying out researches on those problebis which 

 are admittedly urgent. Probably by means of the 

 judicious expenditure of a relatively small sum of 

 money for a few years a great deal of valuable food- 

 stuffs would be saved from destruction by insects and 

 other grain pests. 



The essential characteristics of United States 

 climates is the subject of an article by Prof. R, de C. 

 Ward, of Harvard University, in the Scientific Monthly 

 for December last. For descriptive details the United 

 States is subdivided into climatic districts, and these 

 are called the Eastern, the Gulf, the Plains, the 

 Plateau, and the Pacific ; with the three last-named 

 a further subdivision between north and south is sug- 

 gested by the difference of latitude. Temperature, 

 rainfall, and other climatic conditions are given in 

 fair detail for the several districts, and a comparison 

 is made of the different advantages for fruit-growing, 

 farming, and general agriculture. The movements of 

 storms and cyclonic disturbances necessarily enter 

 largely into the general explanation for rains experi- 

 enced, the disturbances travelling generally from west 

 to east. The article gives a very general idea of the 

 different meteorological conditions which prevail in 

 various parts of the United States, especially with 

 regard to temperature ; on the whole, it is shown 



