THE ly ADEQUACY OE THE CELL-THEuRY. I I I 



ganization be accomplished at once, before cells are formed, or 

 gradually, while cell-formation is going on. 



If we no longer hesitate to accept Briicke's view that the 

 functions of the cell are proof of organization, although our 

 best microscopes fail to give us any idea of what it consists in, 

 it certainly ought not to be difficult to regard the o.^^ as .a 

 young organism, and the developmental phenomena as proof of 

 organization. Such organization is, in fact, conceded when we 

 speak of the egg as the rudiment of an organism ("Anlage 

 eines Organismus," O. Hertwig), but, nevertheless, we go on 

 insisting that cellular structure is the essence of a higher 

 organization. 



We are so captured with the personality of the cell that we 

 habitually draw a boundary-line around it, and question the 

 testimony of our microscopes when we fail to find such an 

 indication of isolation. We have so long insisted on these 

 boundary-lines as limiting homologies that we find it extremely 

 difficult to ignore them. How difficult it is, for example to 

 regard a multicellular nephridial funnel as the exact homologue 

 of the unicellular funnel. If the organ consist of one cell, the 

 tube is ////rcr-cellular ; if of many cells, then it is ////cr-cellular. 

 But we have the "tube" and the "flame" just as perfect with 

 one cell as with many, as Vejdovsky's studies make very 

 certain. How idle, then, to deny homology between two 

 such organs merely because one is infra- and the other inter- 

 cellular. And yet that is precisely what we have been accus- 

 tomed to do. 



Now this one case illustrates, as I believe, a general truth of 

 no little importance. TJic nephrostonic is a ncpJirostoiiic all the 

 same whether it consist of one cell, txvo cells, or n/any cells. Its- 

 form and function are hot It independent of the nnmber of com- 

 ponent cells. Cells mnltiply, hnt the organ remains the same 

 throiigliont. So far as homology is concerned, the existence of 

 cells may be ignored. 



May \\Q not go further, and say that an organism is an organ- 

 ism from the egg onward, quite independently of the number 

 of cells present .^ In that case continuity of organisation would 

 be the essential thing, while division into cell-territories might 



