SECOND LECTURE. 



A DYNAMICAL HYPOTHESIS OF INHERITANCE. i 



JOHN A. RYDER. 



The doctrine of the preformation of an organism in the 

 germ is as inconsistent with fact as with the requirements of 

 dynamical theory. The effects of the preconceptions of pre- 

 formationism have been only too apparent in framing hypothe- 

 ses of inheritance. The now dominant hypothesis is simply an 

 amplification, in the light of numerous modern facts, of the 

 preformationism of Democritus. He supposed that almost in- 

 finitesimally small and very numerous bodies were brought 

 together in the germ from all parts of the body of the 

 parent. These minute representative corpuscles were sup- 

 posed to have the power to grow, or germinate, at the right 

 time, and in the right order, into the forms of the parts and 

 organs of the new being. In this way it was supposed that 

 the characteristics of the parent were represented in a latent 

 form in the germ, which might grow as a whole, by the 

 simultaneous and successive development of the germinal 

 aggregate composed, so to speak, of excessively minute buds, 

 or rudiments of the organs. In such wise also did the suc- 

 cessors of Democritus, namely, Aristotle, Buffon, and Erasmus 

 Darwin, suppose that the inheritance of parental likeness by 

 offspring was to be explained. The later and greater Darwin 

 greatly amplified this hypothesis and proposed, provisionally, 

 to account for the phenomena of inheritance by its help. 

 Conceiving the process somewhat as above supposed, he 



1 It is interesting to note that the views developed in this lecture lead to con- 

 clusions in some respects similar to those held by Professor Whitman in his dis- 

 course entitled : The Insufficiency of the Cell-theory of Development, published in 

 the series of lectures delivered in 1S93. 



