390 ANNUAL BEPOKT SMITHSONIAN INSTITUTION, 1911. 



obeyed, when we recognize the little cross-furrow that separates the 

 blastomeres, two and two, leaving in each case three only to meet at 

 a point in our diagram, which point is in reality a section of a ridge or 

 crest. 



Very few have tried, and one or two (I know) have tried and not 

 succeeded, to trace the action and the effects of surface tension in 

 the case of a highly complicated, multisegmented egg. But it is not 

 surprising if the difficulties which such a case presents appear to be 

 formidable. Even the conformation of the interior of a soap froth, 

 though absolutely conditioned by surface tension, presents great 

 difficulties, and it was only in the last years of Lord Kelvin's life 

 that he showed all previous workers to have been in error regarding 

 the form of the interior cells. 



But what for us does all this amount to ? It at least suggests the 

 possibility of so far supporting the observed facts of organic form on 

 mathematical principles as to bring morphology within or very near 

 to Kant's demand that a true natural science should be justified by 

 its relation to mathematics. 1 But if we were to carry these principles 

 further and to succeed in proving them applicable in detail, even to 

 the showing that the manifold segmentation of the egg was but an 

 exquisite froth, would it wholly revolutionize our biological ideas? 

 It would greatly modify some of them, and some of the most cherished 

 ideas of the majority of embryologists ; but I think that the way is 

 already paved for some such modification. When Loeb and others 

 have shown us that half, or even a small portion of an egg, or a single 

 one of its many blastospheres, can give rise to an entire embryo, and 

 that in some cases any part of the ovum can originate any part of 

 the organism, surely our eyes are turned to the energies inherent in 

 the matter of the egg (not to speak of a presiding entelechy), and 

 away from its original formal operations of division. Sedgwick has 

 told us for many years that we look too much to the individuality of 

 the individual cell, and that the organism, at least in the embryonic 

 body, is a continuous syncytium. Hofmeister and Sachs have 

 repeatedly told us that hi the plant, the growth of the mass, the 

 growth of the organ, is the primary fact; and De Bary has summed 

 up the matter in his aphorism, Die Pflanze bildet Zellen, nicht die 

 Zelle bildet Pflanzen. And in many other ways the extreme position 

 of the cell theory, that the cells are the ulimate individuals, and 

 that the organism is but a colony of quasi independent cells, has of 

 late years been called in question. 



There are no problems connected with morphology that appeal so 

 closely to my mind, or to my temperament, as those that are related 



i " Ich. behaupte aber dass in jeder besonderen Naturlekre nur so viel eigentliche Wissenschaft angetroffen 

 werden konne, als darin Matheniatik anzutreffen ist." Kant, in Preface to Metaphys. Anfangsgriinde 

 der Naturwissenschaft (Werke, ed. Hartenstein, vol. iv., p. 360). 



