174 CONTINUITY OF THE GERM-PLASM AS THE [IV. 



position comes into operation or not. The continuity of the 

 germ-plasm is amply sufficient to account for such a pheno- 

 menon, and I do not believe that any objection to my hypothesis, 

 founded upon the actually observed phenomena of heredity, 

 will be found to hold. If it be accepted, many facts w^ill appear 

 in a light different from that which has been cast upon them by 

 the hypothesis which has been hitherto received, — a hypothesis 

 which assumes that the organism produces germ-cells afresh, 

 again and again, and that it produces them entirely from its 

 own substance. Under the former theory the germ-cells are 

 no longer looked upon as the product of the parent's body, at 

 least as far as their essential part — the specific germ-plasm — is 

 concerned : they are rather considered as something which is 

 to be placed in contrast with the tout ensemble of the cells which 

 make up the parent's body, and the germ-cells of succeeding 

 generations stand in a similar relation to one another as a series 

 of generations of unicellular organisms, arising by a continued 

 process of cell-division. It is true that in most cases the genera- 

 tions of germ-cells do not arise immediately from one another 

 as complete cells, but only as minute particles of germ-plasm. 

 This latter substance, however, forms the foundation of the 

 germ-cells of the next generation, and stamps them with their 

 specific character. Previous to the publication of my theory, 

 G. Jager^ and later M. Nussbaum^, have expressed ideas upon 

 heredity which come very near to my own ^. Both of these 



1 Jager, '■ Lehrbuch der allgemeinen Zoologie,' Bd. II. Leipzig, 1878. 



2 M. Nussbaum, ' Die Differenzirung des Geschlechts im Thierreich,' 

 Arch. f. Mikrosk. Anat., Bd. XVIII. 1880. 



^ I have since learnt that Professor Rauber of Dorpat also expressed 

 similar views in 1880 ; and Professor Herdman of Liverpool informs me 

 that Mr. Francis Galton had brought forward in 1876 a theory of heredity 

 of which the fundamental idea in some ways approached that of the 

 continuity of the germ-plasm ('Journal of the Anthropological Institute,' 

 vol. v ; London, 1876).— A. W., 1888. 



[A less complete theory was brought forward by Galton at an earlier 

 date, in 1872 (see Proc. Roy. Soc. No. 136, p. 394). In this paper he 

 proposed the idea that heredity chiefly depends upon the development 

 of the offspring from elements directly derived from the fertilized ovum 

 which had produced the parent. Galton speaks of the fact that ' each 

 individual may properly be conceived as consisting of two parts, one of 

 which is latent and only known to us by its effects on his posterity, 

 while the other is patent, and constitutes the person manifest to our 

 senses. The adjacent and, in a broad sense, separate lines of growth in 

 which the patent and latent elements are situated, diverge from a 



