290 PROTOPLASM 



always kept this problem in view ; and the firm conviction 

 that there was in this direction a prospect of arriving at a 

 comprehension of protoplasmic movements was one of the 

 main incentives of the investigations described in this work. 



In 1880 Eindfleisch published his ideas upon the 

 supposed causes of protoplasmic movements, which have 

 certain points in common with the view that surface tension 

 comes into play in this process. Eindfleisch adopted the 

 theory of the reticular framework of protoplasm, and sought 

 to show that the intimate interpenetration of two different 

 substances, i.e. the framework and the intervening matrix, 

 which follows from such a structure of protoplasm, was of 

 fundamental importance for the origin of processes of 

 movement. His hypothesis asserts that the adhesion of the 

 two interpenetrating ' substances forms the active principle 

 in the origin of processes of movement ; alterations of their 

 adhesion necessarily produce small movements, the sum 

 total of which bring about the observed effect. He tries to 

 support this assumption by reference to the phenomena of 

 movement in fluids. For instance, he refers to the movements 

 which a drop of glacial acetic on a slide, or a fine layer of 

 oil on water, shows when warmed. In these cases, however, 

 there is no doubt that surface tension is the cause of the 

 changes of form and phenomena of movement, so that it 

 may well be supposed that Eindfleisch had in reality 

 imagined this to be if anything the efficient cause. Besides, 

 it scarcely requires any special discussion to show that no 

 explanation is possible in the way indicated by him, since 

 the hypothesis of a reticular framework, which nevertheless 

 must be fluid, in order to exhibit changes of form and 

 phenomena of movement under the assumed conditions, does 

 not seem possible.^ 



In the year 1886 Berthold arrived at the view that the 

 protoplasmic streamings in vegetable cells had their cause in 



^ It may be mentioned here q^uite briefly that Geddes (1883) developed a 

 hypothesis which seeks to refer amoeboid movement and the contractions of 

 striped muscles to the so-called phenomena of aggregation, such as Darwin 

 observed in the protoplasm of insectivorous plants. Geddes's view is not, 

 however, perfectly intelligible to me. 



