( ^'1^ ) 



SUMMAKY 



OF CURRENT RESEARCHES RELATING TO 



ZOOLOaY AND BOTANY 



(principally Invertehrata and Crijptogamia), 



MICROSCOPY, &c., 



INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS. 



ZOOLOGY. 



A. VERTEBRATA :— Embryology, Histology, and General. 



a. Embryology. f 



Darwinism. I — Under this title Mr. A. E. Wallace has published an 

 important and most interesting work in which he gives an exposition of 

 the theory of Natural Selection, with some of its applications. Mr. 

 Wallace, who remains true to his belief in the overwhelming importance 

 of Natural Selection in the production of new species, criticizes very 

 forcibly many recent speculations and theories. While using for his 

 purpose a number of facts already cited, he brings forward a quantity 

 of new evidence, especially on the subject of variations within the limits 

 of a species. He reduces the importance of sexual selection as a factor 

 in producing new species, and he claims for his book the position of 

 being the advocate of pure Darwinism. It is only necessary for us to 

 chronicle the appearance of this important work. 



Heredity.§ — Mr. J. A. Thomson furnishes a historical summary of 

 theories of heredity, discussing (a) those which sought to explain tho 

 uniqueness of the germ-cells by special hypotheses such as those 

 involved in " pangenesis " ; (b) the gradual elaboration of the doctrine of 

 germinal continuity, from Owen and Haeckel to Jaeger and Weismann ; 

 (c) the auxiliary theories of " organic memory," " perigenesis," chemical 

 continuity, &c., which seek to make the fact of reconstruction more 

 intelligible. 



As to the inheritance of acquired characters, the author summarizes 

 the various opinions, emphasizing Weismann's scepticism. The various 

 criticisms of Weismann's conclusions based on concrete cases, on patho- 

 logical evidence, and on the general theory of evolution are briefly 

 summed up, while the author urges that the general symbiosis of the 

 organism, the common medium of the blood, the frequency of inter- 



* The Society are not inteiided to be denoted by the editorial "we," and they do 

 not hold themselves responsible for the views of the authors of the papers noted 

 nor for any claim to novelty or otherwise made by them. The object of this part of 

 the Journal is to present a summary of the papers as actually published, and to 

 describe and illustrate Instruments, Apparatus, &c., which are either new or have 

 not been previously described in this country. 



t This section includes not only papers relating to Embryology properly so called, 

 but also those dealing with Evolution, Development, and Reproduction, and allied 

 subjects. X ' Darwinism,' 8vo, London, 1889, viii. and 494 pp. (37 figs.). 



§ Proc. R. Soc. Edin., 1888-9, pp. 98-116. 



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