August Friedrich Leopold Weismann. xxxiii 



consequence of gemmules dispatched to the germ by environmentally 

 modified body-cells, Weismann looked for the origin of variation in the 

 kaleidoscopic combination of innumerable ancestral factors brought about 

 by sexual reproduction. He thus sought to explain the meaning of sexual 

 reproduction itself as well as the events which lead up to the fusion of the 

 male and female germ-cells. 



"The subjects thus briefly enumerated, treated in eight memoirs published 

 between 1881 and 1888, were translated, and appeared in a collected form in 

 this country as 1 Essays upon Heredity and Kindred Biological Problems ' 

 (1889). The translation of four additional memoirs (1886-1891) was 

 published as a second volume in 1892, the year in which he produced 

 The Germplasm,' translated by Prof. W. Newton Parker and published in 

 this country in 1893. An elaborate and remarkable hypothesis, ' Germinal 

 Selection' (1896), was followed by the comprehensive treatise on the 

 evolution theory, which brought his long and fruitful life-work to a close. 

 The two volumes passed through three editions between 1902 and 1913, the 

 English translation by Prof, and Mrs. J. Arthur Thomson appearing in 1904, 

 the year of the Festschrift which celebrated Weismann's seventieth birthday." 



It is truly said in the Academical Vade-mecum (1904) of his University 

 that Weismann considered his chief duty as a teacher was to spread the 

 doctrines of Darwin, and that the aim of all his investigations was to confirm 

 and further develop them. 



In these years of revelation it is well to be reminded of the words of 

 warning and advice to younger men uttered by Weismann on his seventieth 

 birthday : — 



" You will not be among those thoughtless people who believe that the 

 main object of science is to make useful discoveries .... steam eugines, 

 telegraphs, telephones, antiseptic treatment of wounds, knowledge of fever 

 parasites in the blood, and the like. However important these and many 

 other advances are for humanity, they would never have taken place at all 

 if research had looked to them as its sole object. They are but by-products 

 of the investigator's workshop, where the real aim must always be pure 

 knowledge for its own sake, unbiassed by secondary efforts. Antiseptic 

 treatment could scarcely have been discovered without a previous knowledge 

 of the lowest and smallest of known organisms, the bacteria, and the life- 

 histories of many harmless forms. Or how could we ever have come to know 

 of the parasites of malaria living in the blood if we had not previously 

 studied similar lowly forms of life inhabiting water and other media ? And 

 these studies were not pursued because it was foreseen that they would one 

 day become splendidly important for us, any more than Weber and Gauss 

 studied electromagnetism in order to invent the telegraph . 



It is fitting to conclude this brief story of Weismann's life with the true 

 and noble thought contained in his address at the Darwin Centenary 



