J. W. Jenkinson. 



xliii 



eastern field of war when he fell in one of the fierce attacks on the coast of 

 Gallipoli. Thus died in the service of his country a man of indomitable 

 courage, great physical and mental energy, and remarkable powers of 

 endurance. His loss was felt as a painful blow by his many friends and 

 colleagues in Oxford, and as a severe loss to zoological science. 



Jenkinson's scientific work was almost entirely devoted to Embryology. 

 His earliest original contribution was " A Eeinvestigation of the Early 

 Stages in the Development of the Mouse " (' Quart. Jour. Micro. Sci.,' 

 vol. 43, 1900), an able criticism of the views of Eobinson and Assheton 

 concerning the origin of the germ-layers and trophoblast. It was founded 

 on work partly carried out in the laboratory of the famous Dutch 

 embryologist, Prof. Hubrecht, in Utrecht, to which Jenkinson had paid 

 several visits. Soon afterwards he wrote " Observations on the Histology and 

 Physiology of the Placenta of the Mouse " (' Tijdschr. Nederl. Vereenig.,' 

 vol. 7, 1902), and some years later on the placenta in Ungulates (' Proc. Zool. 

 Soc.,' 1906). In a paper " On the Development of the Ear-bones in the 

 Mouse "(' Jour. Anat. and Physiol.,' vol. 45, 1911) he successfully attacked 

 the difficult problem of the first appearance of these structures, and showed 

 that, in the very earliest stages, the stapes is connected with the hyoid arch, 

 and the incus and malleus with the mandibular arch. Quite lately he 

 published (Oxford, 1913) a little text-book on ' Vertebrate Embryology,' 

 giving an excellent account of the germ-cells, the germ-layers, and the 

 placenta. 



But Jenkinson soon became more interested in experimental embryology — 

 a comparatively new science little studied in England, and offering an 

 attractive and boundless scope for research. After publishing a detailed 

 description of the maturation and fertilisation processes in the Axolotl 

 (' Quart. Jour. Micro. Sci.,' vol. 48, 1904), he wrote a number of valuable 

 papers on the relation of the symmetry of the egg to the symmetry of the 

 embryo in the frog, on the effect of various salts and other substances on 

 development, and kindred subjects (' Quart. Jour. Micro. Sci.,' 1 Biometrika,' 

 ' Brit. Ass. Eeports,' ' Archiv f. Entwickelungs-mechanik '). His best known 

 and perhaps most important work is the ' Experimental Embryology ' 

 {Oxford, 1909). Although several books on the subject had appeared 

 abroad, this was the first comprehensive text-book published in England 

 on a new and fascinating branch of zoology. It contains a summary and 

 discussion of practically all the results that had been obtained up to the 

 time of its publication. Clear exposition and sound judgment distinguish 

 this work, in which the author finally pronounces against the neo-vitalistic 

 doctrines of Driesch. The appearance of Jenkinson's book stimulated 

 interest in experimental embryology in this country, and the premature 

 death of the author leaves a gap in the ranks of zoological researchers which 

 it will be difficult to fill. 



E. S. G. 



VOL. LXXX1X. — B. 



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