426 



SCIENCE 



[N. S. Vol. XXXIV. No. 875 



pier phenomenon of a "laminar system," 

 uncomplicated by the presence of a solid 

 framework ; and here, in the earliest stages 

 of segmentation, it is easy to see the corre- 

 spondence of the planes of division with 

 what the laws of surface-tension demand. 

 For instance, it is not the case (though the 

 elementary books often represent it so) 

 that when the totally segmenting egg has 

 divided into four segments, the four parti- 

 tion walls ever remain in contact at a single 

 point; the arrangement would be unstable, 

 and the position untenable. But the laws 

 of surface-tension are at once seen to be 

 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, 

 multi-segemented egg. But it is not sur- 

 prising 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 sci- 

 ence should be justified by its relation to 

 mathematics.^ But if we were to carry 



°"Ich behaupte aber dass in jeder besonderen 

 Naturlehre nur so viel eigentUche Wissensehaft 

 angetrofifen werden konne, ala darin Mathematik 

 anzutreflfen ist. ' ' — Kant, in preface to ' ' Metaphys. 



these principles further and to succeed in 

 proving them applicable in detail, even to 

 the showing that the manifold segmenta- 

 tion 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 blastomeres, 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 opera- 

 tions 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. Hof- 

 meister and Sachs have repeatedly told us 

 that in 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, nieht die Zelle bildet Pflanzen." 

 And in many other ways, as many of you 

 are well aware, the extreme position of the 

 cell-theory, that the cells are the ultimate 

 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 to mechanical considerations, to 

 mathematical laws, or to physical and 

 chemical processes. 



I love to think of the logarithmic spiral 



Anfangsgriinde der Naturwissensehaf t " (Werke, 

 ed. Hartenstein, Vol. IV., p. 360). 



