GENEOLOGICAL. 401 



portant are (a) the minute study of the history of 

 the germ-cells by which life is continued from gen- 

 eration to generation; (&) the statistical study of 

 the measurable characters of successive generations; 

 and (c) the testing of various conclusions by ex- 

 perimental breeding. The first may be illustrated 

 by reference to Weismann's Germ-Plasm (1893) and 

 Wilson's The Cell in Development and Inheritance 

 (2nd ed., 1900) ; the second by Galton's Natural In- 

 heritance (1889) and Karl Pearson's memoirs; and 

 the third by Professor Cossar Ewart's Penycuik Ex- 

 periments (1899). 



Facts of Inheritance. We do not propose to ex- 

 pound the facts of inheritance, but merely to indi- 

 cate the present position of biology by a brief 

 reference. 



(I.) The physical basis of inheritance is in the 

 fertilised ovum. Since the egg-cell is often micro- 

 scopic and the sperm cell may be only -nruvsw of 

 the ovum's size, it seems to many difficult to conceive 

 how there can be room in these minute elements for 

 the complexity of organisation supposed to be requi- 

 site; and the difficulty will be increased if the cur- 

 rent opinion be accepted that only the nuclei within 

 the germ-cells are the true bearers of the hereditary 

 qualities. It must be at once admitted that it is 

 quite impossible to form any mental picture of the 

 fact which the word potentiality implies. 



To the question: What accounts for the poten- 

 tiality of the germ-cell, what makes it, in con- 

 trast to any other cell, able to develop into an 

 organism ? only two plausible answers have been 

 given. To the preformationists, no objective answer 

 was forthcoming, and the majority fell back upon 

 a hypothesis of hyperphysical agencies. 



