AMCEBOID MOVEMENT 307 



in which a cell-sap is wanting, special relations are in any 

 case presented which cannot be gone into until later on. 

 In addition to this difficulty, which, as it seems to me, alone 

 suffices to prove the untenability of Quincke's explanation, 

 there is yet a further one, namely, that since the cuticular 

 layer is everywhere in close contact with the oily utricle, it 

 does not in my opinion seem very clear why local extensions 

 of the so-called albumen soap should arise, since the formation 

 of albumen soap should go on along the whole surface of 

 contact between the cuticular layer, which is everywhere 

 albuminous, and the oily utricle. 1 Hence these suppositions 

 scarcely seem to supply the conditions for the appearance of 

 definite and often quite one-sided streaming movements. 



Since also the principles from which Quincke starts in 

 his explanation do not seem to me to be adequate, it would 

 be unnecessary at the outset to discuss more accurately the 

 explanations which he gives for special cases, such as cir- 

 culatory streaming, development of pseudopodia, etc. 



(/) My own View of the Explanation of amoeboid 

 Movement 



At the commencement of this chapter it was pointed out 

 that I should consider the possibility of an explanation, 

 which my conception of protoplasm furnishes in the case of 

 the simpler phenomena of movement at least, as a confirma- 

 tion of the correctness of the interpretation which has been 

 attempted of its structural relations. 



In passing on to attack this question more closely, I 

 must remark at the outset that in spite of all my efforts 

 such an explanation seems at present feasible only for 

 amoeboid movement in the strict sense, while other modifi- 

 cations of it, especially the formation of the fine pseudopodia 

 of numerous Sarkodina, obtain no explanation. 



The movement of simple Amoebae, such as A. guttula, 

 Umax, and Uattce, and Pelomyxa, is so exceedingly similar 



1 It could only be assumed in some way that oxidation, and hence the 

 appearance of free fatty acid, took place locally in the oily membrane. 



