3 o6 PROTOPLASM 



(1) an external "protoplasmic utricle," (2) the hyaline cuti- 

 cular layer (Hautschiclit), and (3) the granular protoplasm. 

 The so-called protoplasmic utricle is supposed to be an 

 immeasurably thin, fluid oil membrane, for the most part in- 

 visible. Without Quincke's making any definite statement 

 with regard to the fact, it may be assumed that he was led to 

 suppose the existence of a so-called protoplasmic utricle by 

 the protoplasmic membrane of Pfeffer and others. Now the 

 streamings are supposed to arise from the formation of a 

 saponaceous compound (the so-called albumen soap) produced 

 by the action of the albumen of the cuticular layer upon the 

 fatty acid set free, by the action of oxygen, from the oil of 

 the protoplasmic utricle. This soap produces local diminu- 

 tions of surface tension on the inner side of the protoplasmic 

 utricle, and thus calls forth extension - currents. Let us 

 pause for a moment over this fundamental conception with 

 regard to the streamings which Quincke has put forth. 

 I do not think that it appears admissible, and in the first 

 place, chiefly from the following reasons. According to 

 Quincke's view the region in which the streamings take their 

 origin is situated close under the cell membrane, namely, at 

 the boundary between the immeasurably fine oily utricle and 

 the cuticular layer. Now it is known quite for certain, and 

 has often been demonstrated, that the most external layer of 

 protoplasm, which touches upon the cell membrane, is beyond 

 doubt quiescent in a large series of cases, and in fact that, as 

 in Chara, for example, the entire chlorophyll-bearing cortical 

 layer of the protoplasm is in a state of rest. A similar 

 condition is also shown by the Ciliata with cyclosis of 

 the endoplasm, where in the same way the cortical 

 protoplasm and the ectoplasm are in a state of rest, while 

 the internal protoplasm streams. In these cases it is 

 impossible that the seat of the movement should be found 

 at the internal surface of such an external utricle of oil, 

 but there is every reason, on the other hand, for believing 

 that, as has already been stated above in connection with 

 the views of Nageli, Schwendener, and Berthold, the cause of 

 movement has its seat at the limiting surface between the 

 protoplasm and the cell-sap. In the cyclosis of Infusoria, 



