THE LIVING SUBSTANCE. 83 



ceaseless series of these activities going on for hours, the sub- 

 stance heaping itself up here and there in lumps, and then again 

 forming papillose processes over wide areas, and again, a thick, 

 smooth pellicle. 



Little surface tension for the mass would seem to persist 

 under such conditions. As a matter of fact, the peripheral 

 pellicle itself relaxed in places, extending its substance no 

 longer in filose processes but in amoeboid lumps, or knots, or 

 films. Yet, all the while, the phenomena of karyokinesis and 

 of actual cell cleavage went on ; more slowly than in normal 

 eggs, but still without pause. First into four, then into eight, 

 then into sixteen cells did the mass divide, forming internally 

 perfect walls for all the cells, though there never occurred any 

 actual separation of these from each other. Still, in the usual 

 acceptation of the term, the cells divided ; that is, their mass 

 was subdivided by, so-called, cell walls. 



In the ectosarc formed by the egg substance after being 

 squeezed into the water, structural reduction, and then in some 

 cases, a reappearance of Butschli's structure, were observed. 

 The finest vesicles which could be detected showed no change 

 of contour, so that here, as in protoplasmic ectosarc, a structure- 

 less appearance could hardly be attributed to mere stretching 

 of the alveolar lamellae, especially as the meshwork became 

 often thicker and optically more conspicuous, rather than more 

 tenuous and less obvious as reduction went on. 



When pressure was applied to eggs in 4-16-celled stages, in 

 which the cells last divided were still optically separated, fila- 

 ments connecting the cells were seen to become thicker, denser, 

 more refractive, and yellowish in tone. At the same time, if 

 the pressure were slow, the viscosity and resistance of the cell 

 mass also increased; and the cells showed a similar change in 

 quality of their pellicular stuff, while many peripheral processes 

 were withdrawn. 



Rapid, or sudden, pressure effected a separation of the cells 

 more readily, but seemed to be followed by the same optical 

 changes in the cell protoplasm. If actually separated, but 

 without rupturing the membrane perceptibly, as was done a 

 number of times by pressure of a mixed rolling and squeezing 



