220 PROTOPLASM 



(a) Aggregate Condition of Protoplasm 



In order, however, to approach this question, we must 

 first of all come to a decision with regard to the aggregate 

 condition of protoplasm, since the solution of the question 

 turns essentially upon this preliminary inquiry. The point 

 has notoriously been much disputed, and an opinion has 

 even been expressed that one cannot properly speak at all 

 of an aggregate condition of protoplasm, in the same sense 

 as of that of a homogeneous body (Briicke, 1861), for the 

 very reasons that protoplasm is not a homogeneous body, 

 but a mixture of solids and fluids. 



I would gladly avoid entering into the historical aspect of 

 this question, but it does not seem possible to discuss the 

 problem clearly without such a brief review. The older 

 observers were notoriously fairly united in their conception of 

 protoplasm as a slimy, rather viscid fluid. This view was 

 essentially established by the studies of prominent investiga- 

 tors, especially in the fifties and sixties, during which period 

 the protoplasm question awakened a lively interest. Max 

 Schultze's investigations on the protoplasm of E-hizopods and 

 vegetable cells and their phenomena of movement (1854-63), 

 on whose side Haeckel (1862, p. 90 et seq.) ranked himself as 

 the upshot of his extended labours on Rhizopods, Radiolaria, 

 etc., and finally the studies of Kiihne (1864) upon protoplasm, 

 especially confirmed this view. The principal support for it 

 was obtained from the relations of the phenomena of streaming 

 movement which gave the observer the impression of a sub- 

 stance in a state of flux, and therefore fluid ; and further 

 from the flowing together of protoplasmic processes, the taking 

 up of solid particles into the interior of the protoplasm, and the 

 tendency of isolated portions of protoplasm to assume a spherical 

 form. 



A reaction against this conception was started as far back as 

 1861 by Briicke. Briicke disputed a priori the possibility of 

 fluid protoplasm being able to carry on all the complicated 

 functions of the cell. The cell, or more properly its protoplasm, 

 must therefore possess, in addition to its molecular structure, a 

 "special structure" or "organisation." Hence all protoplasm 

 must consist of solid and fluid portions. To inquire into the 

 condition of the protoplasm in the aggregate would therefore be 

 really just as absurd as to discuss the same question in reference 



