THE THEORIA GENERATIONIS. 28 1 



matter and a concomitant dissipation of motion ; during which 

 the matter passes from an indefinite, incoherent homogeneity 

 to a definite, coherent heterogeneity ; and during which the 

 retained motion undergoes a parallel transformation." If 

 Wolff could have read this sonorous definition he would prob- 

 ably have accepted it as the expression of a general truth, as it 

 is accepted to-day. Still when we compare our views on the 

 development of living organisms with those of Wolff, we observe 

 a vast difference, to which Professor Whitman calls attention 

 when he says^: "The indubitable fact on which we now build 

 is no bit of inorganic homogeneity, into which organization is to 

 be sprung by a coagulating principle, or cooked in by a calidmn 

 innatum, or wrought out by a spinning archaeus, but the ready- 

 formed, living germ, with an organization ait directly front a 

 preexisting, parental organization of the same kind. 



" The essential thing here is, not simply continuity of germ- 

 substance of the same chemico-physical constitution, but actual 

 identity of germ-organization with stirp-organizatio7t!' 



To-day we recognize three conditions of matter : dead 

 matter, undifferentiated living protoplasm, and differentiated 

 living protoplasm. The germ is cut from its parent as organ- 

 ized but undifferentiated living protoplasm ; during ontogeny it 

 is converted into differentiated living protoplasm. Wolff saw 

 no difficulty in leaping with a bound from dead matter to 

 highly differentiated living protoplasm. There are scientific 

 acrobats still living who are not at all afraid of taking a like 

 hop, skip, and jump. The majority of biologists, however, are 

 too heavy with the past century's observations on living matter 

 to be able to leap so fast and so far. They find the distance 

 between dead matter and undifferentiated protoplasm enor- 

 mous — a chasm so wide and deep that they prefer making a 

 long detour to attempting a perilous leap across it. They are 

 more intrepid in passing over the gap, great as it undoubtedly 

 is, which separates the undifferentiated from the differentiated 

 phase of organized matter, the germ from the adult. Current 

 discussion is, therefore, mainly limited to the valuation of the 



1 Whitman, C. O., " Evolution and Epigenesis," Biological Lectures (1894). 

 Boston, Ginn & Co., 1895. p. 212. 



