234 SCIENCE PROGRESS. 



of equilibrium, the limit of imbibition is reached." And 

 also: "Since particles of water may be held fast on the 

 surfaces of the micellae by molecular attraction, so also 

 other matters (lime and siliceous salts, colouring matters, 

 gelatin compounds, etc.) may be deposited on them after 

 they have been taken into the organic body in a state of 

 solution ". So far as my physical knowledge enables me to 

 form a judgment, attributes such as these may justifiably be 

 ascribed to micellse on purely physical grounds and their 

 importance can hardly be overestimated, since the last 

 passage quoted affords a hint as to the nature of the essen- 

 tially vital process of assimilation. It is not my business 

 now to develop a complete theory ; I doubt indeed whether 

 a complete theory is possible in the present state of our 

 knowledge. I have done sufficient for present purposes if 

 I have succeeded in indicating what ideas we may justifiably 

 hold on the subject of protoplasmic structure, and I believe 

 that I have given some good grounds for justification of the 

 views that ; (i) the ultimate visible structure of protoplasm 

 is an alveolar structure ; (2) that the invisible structure of 

 protoplasm is a "micellar" structure in the sense defined 

 above. 



But before I proceed I must enter a caveat against 

 being considered as an adherent of the micellar theory of 

 Nageli. I cannot enter here into my reasons, but I may 

 say that the further theories which Nageli assumes to 

 be the necessary consequences of the existence of micellae, 

 do not appear to me to be necessary consequences at all ; 

 indeed I part company with him at once when I express my 

 conviction that the hypothesis of a micellar structure is 

 compatible with the alveolar structure described by 

 Butschli. 1 



1 Since the above argument was first written out the work of Yves 

 Delage has come into my hands. It is most gratifying to find that the 

 opinions of so distinguished an author accord so exactly with my own. The 

 reader who finds my argument involved and laborious may turn with profit 

 to Delage's book, in which he will find a lucidity of expression and a 

 precision in argument which I can only envy without hoping to imitate. It 

 is worth while quoting the following passages here: "On peut accorder 



