THE PROTOPLASMIC SYSTEM 



which have been brought about through the action of the 

 fixing solution in dissolving out fat, yolk or other cyto- 

 plasmic inclusions. Compare the pictures given, (Fig. 22) 

 of a living, (Fig. 2a) of a poorly fixed, and (Fig. 2b) of a 

 properly fixed egg. In Figs. 22 and 2b oil-drop and yolk- 

 sphere are intact. When one bears in mind that Fig. 2b 

 is from a very thin section, about one-thirtieth of the entire 

 egg, and that the larger inclusions present can very easily 

 be displaced in sectioning, the picture is all the more con- 

 vincing: the resemblance to Fig. 22 is striking. But 

 compare Fig. 2a — a mesh-work like a fish-net. From 

 pictures inferior to this (Fig. 2a), wholly disregarding the 

 structure seen in the living egg, Wilson derived his support 

 of the alveolar theory of protoplasmic structure.^ When 

 one speaks of the physical basis of life and refers only to 

 the morphology of the cell, one is misleading- — doubly so 

 if one has in mind a dead cell showing mostly holes. True, 

 protoplasm is the physical, i.e., the corporeal basis of life; 

 also in the fixed state this basis is of interest. But we shall 

 not understand it, if first we vacuolate it and then ascribe 

 to the holes essential meaning without knowledge even as 

 to the significance of the substances which we replaced by 

 holes. On the other hand, to say that the cytoplasm of 

 the living cell is alveolar in structure because the holes 

 of the dead cell were occupied by formed bodies is to give 

 new meaning to the term, alveolus; I can not see how a 

 droplet of fat or a spherical yolk-mass can be designated 

 an alveolus. I have often pressed them out of an egg into 

 sea-water where they remain intact. If they are moved by 

 centrifugal force from one to another region of the cell, 

 they do not leave empty spaces behind them. Hence, 

 neither they nor the places they occupy in the fluid cyto- 

 plasm are alveoli. 



1 Wilson, 1^26; but cf. Mathews, igo6. 

 ~ Wilsoyi, I.e. 



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