March 1, 1895.] 



SCIENCE. 



245 



for trained investigators. Its biological 

 laboratory affords advantages wbiph are 

 each year more widely ai)preciated, and one 

 has but to glance over the titles of the papers 

 listed in the appendix to the volume under 

 consideration, to be impressed with the 

 scientific vigor which characterizes both its 

 staff and pupils. 



The ten lectures for 1894 bear the follow- 

 ing titles : I. ' The Mosaic Theory of De- 

 velopment,' by E. B. Wilson. II. ' The 

 Fertilization of the Ovum,' by E. G. Conk- 

 lin. III. ' On Some Facts and Principles 

 of Physiological Morpliology,' by Jac(iues 

 Loeb. lY. ' Dynamics of Evolution,' by J. 

 A. Ryder. V. 'On the Nature of Cell-Or- 

 ganization,' by S. Watiise. VI. ' The In- 

 adequacy of the Cell-Theoi'y of Develop- 

 ment,' by C. O. Whitman. VII. ' Bdellos- 

 toma Dombeyi Lac' by Howard Ayres. 

 VIII. ' The Influence of External Condi- 

 tions on Plant Life," l)y W. P. Wilson. IX. 

 ' Irrito Contractility in Plants,' by J. Miur- 

 head McFarlane. X. ' The Marine Biolog- 

 ical Stations of Euroiie,' by Bashford Dean. 



Of these papers more than one-half are 

 concerned in a presentation of the results of 

 modern research into tlie activities of the 

 living cell, and it would be diffioult to di- 

 rect a student to any one volume from 

 which he might gain a clearer idea, or find 

 a more satisfactory discussion, of the pres- 

 ent condition of theory and established fact 

 concerning the cell state. Prof. E. B. Wil- 

 son strikes the key-note of the motive 

 which runs through tlie book when he calls 

 attention, on the first liage, to the remark- 

 able change of front which has tiiken place 

 during recent years respecting the germ- 

 layer theory— ^namely : (a) the growing re- 

 cognition of the inadc(iuacj' of a theory of 

 development which practically ignores the 

 pregastrular stages of the ovum; and (6) 

 the tendency to resume the attempts of 

 Briicke and others to formulate a pre-or- 

 ganization theory which should account for 



the evident organization of the cell, by the 

 postulatioii of primary elements, or bearers 

 of cell qualities; the 'physiological units' 

 of Herbert Spencer, the ' gemmules ' of 

 Darwin, the ' Micelke ' of Niigeli, the ' plas- 

 tidules ' of Elsberg and Haeckel, the ' ino- 

 tagmata ' of Th. Engelmann, the 'pangenes ' 

 of De Vries, the • plasomes ' of AViesner, 

 the • idioblasts ' of Hertwig, the ' biophores ' 

 of Weismann, and finally the ' idiosomes ' 

 of Whitman, in which may be found ' the 

 secret of organization, growth and develop- 

 ment.' 



The tendency in modern biology is, in 

 other words, to rob the cell of its leadership 

 in the phenomena of organization, and to 

 regard it as but a 'biotome,' life epoch, or 

 form-phase; correlated with a series of vis- 

 ible cell-aggregates (organs and tissues) on 

 the one hand, and to another series of invis- 

 ible aggi'egates of diminishing complexity, 

 which terminate fiuallj' in protoplasmic 

 molecules variousljr designated, as indicated 

 above. These living molecules are pointed 

 out as the foundation of organization, and 

 the protoplasmic molecule, the ' Specifische 

 Bildungstoile " of Sachs, as the ' essential 

 archetectonic element ;' furnisliing a com- 

 mon basis for evei-y grade of organization, 

 but 'subject to a regenerative and forma- 

 tive power existing as one and the same 

 thing throughout the organic world' (Whit- 

 man). The prevailing thought of the book 

 seems to be expressed bj- Eyder in the con- 

 viction "that experimental investigation in 

 embryologj^ will make no solid progress 

 until all such conceptions as gemmules, 

 biophores and idiosomes are abandoned," 

 and in the dictum of Loeb that •' all life 

 phenomena are determined by chemical pro- 

 cesses." We are asked to concur m the 

 admission that "the phenomena of life are 

 ultimately physical in their nature <and are 

 to be treated in detail as physical problems." 



We may derive from these essays a no- 

 tion of the drift of biological thought in the 



