INADEQUACY OP NATURAL SELECTION, ETC. 629 



It is as though the pseudopodia of imprisoned rhizopods were 

 fused with the pseudopodia of adjacent imprisoned rhizopods. 

 We cannot reasonably suppose that the continuous network of 

 protoplasm thus constituted has been produced after the cells 

 have become adult. These protoplasmic connections must have 

 survived the process of fission. The implication is that the cells 

 forming the embryo-plant retained their protoplasmic connections 

 while they multiplied, and that such connections continued 

 throughout all subsequent multiplications — an implication which 

 has, I believe, been established by researches upon germinating 

 palm- seeds. But now we come to a verifying series of facts 

 which the cell-structures of animals in their early stages present. 

 In his Monograph of the Development of Peripatus Capensis, Mr. 

 Adam Sedgwick, F.R.S., Reader in Animal Morphology at Cam- 

 bridge, writes as follows : — 



" All the cells of the ovum, ectodermal as well as cndodermal, are connected 

 together by a fine protoplasmic reticulum." (p. 41) 



" The continuity of the various cells of the segmenting ovum is primary, 

 and not secondary ; i. c, in the cleavage the segments do not completely sepa- 

 rate from one another. But are we justified in speaking of cells at all in this 

 case ? The fullt/ segmented ovum is a syncytium^ and there are not and have 

 not been at any stuye cell limi'.sy (p. 41) 



" It is becoming more and more clear every day that the cells composing 

 the tissues of animals are not isolated units,, but that they are connected with 

 one another. I need only refer to the connection known to exist between 

 connective tissue cells, cartilage cells, epithelial cells, &c. And not only may 

 the cells of one tissue be continuous with each othar, but they may also be 

 continuous with the cells of other tissues," (pp. 47-8) 



" Finally, if the protoplasm of the body is primitively a syncytium, and the 

 ovum until maturity a part of that syncytium, the separation of the generative 

 products does not differ essentially from the internal gemmation of a Pioto- 

 zoon, and the inheritance by the offspring of peculiarities first appearing in 

 the parent, though not explained, is rendered less mysterious ; for the proto- 

 plasm of the whole body being continuous, change in the molecular constitu- 

 tion of any part of it would naturally be expected to spread, in time, through 

 the whole mass." (p. 49) 



Mr. Sedgwick's subsequent investigations confirm these conclu- 

 sions. In a letter of December 27, 1892, passages which he 

 allows me to publish run as follows : — 



"All the embryological studies that I have made since that to vrhich 

 you refer confirm me more and more in the view that the connections 

 between the cells of adults are not secondary connections, but primary, dating 

 from the time when the embryo was a unicellular structure. . . . ]\Iy 

 own investigations on this subject have been confined to the Arthropoda, 

 Elasmobranchii, and Aves. I have thoroughly examined the development 

 of at least one kind of each of these groups, and I have never been able to 

 detect a stage in which the cells wore not continuous with each other ; 

 and I have studied innumerable stages from the beginning of cleavage 

 onwards." 



So that the alleged independence of the reproductive cells 



