268 PROTOPLASM 



appeared a priori more hopeful, if the explanation of the 

 so-called sarcode or protoplasmic movements had been 

 chosen as the starting-point, and contraction proper had 

 been treated as a special or subordinate case, which attains 

 its full development under certain conditions. 



Investigation was, however, pursued, as has been re- 

 marked, in the opposite direction from the fifties onwards, 

 since it was thought necessary to make use of contractility 

 as a general property of protoplasm for the explanation even 

 of the processes of movement and the streamings of simple 

 protoplasmic bodies, such as Khizopods, protoplasm of plant 

 cells, etc. 



Amongst those who took up this standpoint were both 

 M. Schultze (1863) and his opponent Eeichert (1862, 1863), 

 Briicke (1861), Cienkowsky (1863), de Bary (1862 and 

 1864), Haeckel (1862, p. 90 et seq.), Klihne (1864), and 

 numerous others. 



If the process of movement in an Amoeba, or the process 

 of streaming in the protoplasm of a plant cell, was to be 

 explained on the basis of contraction, it was, of course, 

 necessary to assume some kind of organisation in these 

 protoplasmic bodies which would offer a certain analogy 

 to the organisation of higher organisms, since obviously the 

 whole mass could not be contracted evenly if phenomena of 

 locomotion and streaming were to be brought about. The 

 contraction then was confined chiefly to a cortical layer of 

 the protoplasm, which, like a layer of integumental muscles, 

 was supposed to set the remaining protoplasm in movement 

 by local contraction, or to this contractile and therefore 

 changeable cortex a contractile framework or felt work was 



O 



superadded, which 'traversed the entire protoplasmic body 

 (Briicke, 1861; Cienkowsky, 1863, etc.). In general, however, 

 the adherents of the contraction theory scarcely made any at- 

 tempt to explain or to analyse at all more accurately the loco- 

 motory phenomena of simple protoplasmic bodies on the basis 

 of their theory. They contented themselves rather with 

 referring in a general way to contractility as the cause. If 

 they had gone more accurately into the individual cases, the 

 untenability of the theory would have been earlier apparent. 



