222 PROTOPLASM 



movement must have as a postulate " an organisation of the 

 protoplasm," " a peculiar structure in it, which diners essentially 

 from the aggregate condition of viscid fluid bodies in the fact 

 that the molecules of the protoplasm are capable of being un- 

 equally displaced in different directions." Of this alleged 

 postulate of every explanation he makes, however, no use what- 

 ever, either in considering the phenomena of the structure, or of 

 the movement of protoplasm ; the hypothesis evolved by him 

 with regard to protoplasmic movement contains no mention 

 of it. 



In opposition to these efforts, it must be of special interest to 

 us that tAvo observers so experienced in physical matters as 

 Nageli and Schwendener both in 1865 and later in 1877, 

 especially point out the "viscid nature " of protoplasm, somewhat 

 like mucilage ; it may then, of course, possess an organisation with 

 impunity. They derived their proofs chiefly from the flowing 

 together that may frequently be observed in protoplasmic bodies, 

 and the behaviour of swarm spores when they happened to be 

 torn in pieces. 



Briicke's views soon found further defenders. In 1870 

 Hanstein expressed himself to the same effect. It seemed also to 

 him quite unthinkable that from a fluid substance a structure 

 should have been produced which was organic, and " therefore 

 different in itself." For the rest, his ideas of protoplasm at that 

 time were rather obscure. He ascribes to it " a soft and plastic, 

 and yet viscid and formed and self-forming condition." It was 

 said to contain besides fluid parts, " soft solid " ones as well ; it 

 was not a substance but an organism. 



But it was Velten especially who in his works (1873-76) 

 tried to collect further proofs for Briicke's conception. For him 

 also it was an established fact (1873) that protoplasm possessed 

 in any case a complicated organisation, and was not a homogeneous 

 fluid. But how he really represented the matter to himself is 

 not quite clear. In 1876 he declares that protoplasm is com- 

 posed of solid and fluid parts. Thus on p. 138 it is said that 

 "in protoplasm we have a more or less coherent body, possessing 

 the solid aggregate condition, which last may be temporarily 

 exchanged for that of fluid substance." If the latter limitation 

 makes the view first pronounced rather obscure, the following 

 passage (p. 130) adds still further to the obscurity, where it is said 

 " that protoplasm contains solid and fluid parts side by side in the 

 smallest particles of space." Yelten's view is partly based upon 

 structures observed by him (see above, p. 165), partly upon the 

 peculiarities of the phenomena of streaming. He makes sincere 

 efforts to reconcile with his view the tendency of protoplasm to 



