382 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1911. 



nism of the cell), or, on the other, to the ancient conception of a vital 

 element, alien to the province of the physicist. 



No small number of theories or hypotheses, that seemed for a time 

 to have been established on ground as firm as that on which we tread, 

 have been reopened in our day. The adequacy of natural selection 

 to explain the whole of organic evolution has been assailed on many 

 sides; the old fundamental subject of embryological debate between 

 the evolutionists or pref oraiationists (of the school of Malpighi, Haller, 

 and Bonnet) and the advocates of epigenesis (the followers of Aris- 

 totle, of Harvey, of Caspar Fr. Wolff, and of Von Baer) is now 

 discussed again, in altered language, but as a pressing question of the 

 hour; the very foundations of the cell theory have been scrutinized, 

 to decide, for instance, whether the segmented ovum, or even the 

 complete organism, be a colony of quasi independent cells or a living 

 unit in which cell differentiation is little more than a superficial 

 phenomenon; the whole meaning, bearing, and philosophy of evolu- 

 tion has been discussed by Bergson, on a plane to which neither 

 Darwin nor Spencer ever attained; and the hypothesis of a vital 

 principle, or vital element, that had lain in the background for near 

 a hundred years, has come into men's mouths as a very real and urgent 

 question, the greatest question for the biologist of all. 



In all ages the mystery of organic form, the mystery of growth 

 and reproduction, the mystery of thought and consciousness, the 

 whole mystery of the complex phenomena of life, have seemed to the 

 vast majority of men to call for description and explanation in terms 

 alien to the language which we apply to inanimate things; though at 

 all times there have been a few who sought, with the materialism of 

 Democritus, Lucretius, or Giordano Bruno, to attribute most, or even 

 all, of these phenomena to the category of physical causation. 



For the first scientific exposition of vitalism we must go back to 

 Aristotle, and to his doctrine of the three parts of the tripartite soul; 

 according to which doctrine, in Milton's language, created things "by 

 gradual change sublimed, to vital spirits aspire, to animal, to intel- 

 lectual." The first and lowest of these three, the tf>ozh ^ dpemtid), 

 by whose agency nutrition is effected, is tj Ttpihxi] (J>u%rj, the insepa- 

 rable concomitant of life itself. It is inherent in the plant as well as 

 in the animal, and in the Linnsean aphorism, vegetabilia crescunt et 

 vivunt, its existence is admitted in a word. Under other aspects it 

 is all but identical with the <l>uxtj a££i)?tid) and ytwi)xcKTi , the soul of 

 growth and of reproduction ; and in this composite sense it is no other 

 than Driesch's "Entelechy," the hypothetic natural agency that pre- 

 sides over the form and formation of the body. Just as Driesch's 

 psychoid or psychoids, which are the basis of instinctive phenomena, 

 of sensation, instinct, thought, reason, and all that directs that body 



