A HISTORY OF SCIENCE 



missible to the offspring. Professor Weismann came 

 to believe that the apportionment of the nuclear sub- 

 stance, though quantitatively impartial, is sometimes 

 radically uneven in quality; in particular, that the 

 first bisection of the egg - cell, which marks the be- 

 ginning of embryonic development, produces two cells 

 utterly different in potentiality, the one containing the 

 "body plasm," which is to develop the main animal 

 structures, the other encompassing the "germ plasm," 

 by which the racial integrity is 'to be preserved. 

 Throughout the life of the individual, he believed, this 

 isolation continued; hence the assumed lack of influ- 

 ence of acquired bodily traits upon the germ plasm and 

 its engendered offspring. Hence, also, the application 

 of the microscopical discovery to the deepest ques- 

 tions of human social evolution. 



Every one will recall that this theory, born of the 

 laboratory, made a tremendous commotion in the out- 

 side world. Its application to the welfare and progress 

 of humanity gave it supreme interest, and polemics 

 unnumbered were launched in its favor and in its con- 

 demnation. Eager search was made throughout the 

 fields of botany and zoology for new evidence pro or 

 con. But the definitive answer came finally from the 

 same field of exploration in which the theory had been 

 originated the world of the cell and the Marine 

 Biological Laboratory was the seat of the new series 

 of experiments which demonstrated the untenability 

 of the Weismannian position. Most curious experi- 

 ments they were, for in effect they consisted of the 

 making of two or more living creatures out of one, in the 

 case of beings so highly organized as the sea-urchins, 



