WALLACE O, FENN 



381 



♦02 



♦ai 



-0.1- 



m=i.o 



0.1 a2 03 a4 ojy 

 Fig. 4. Graphs showing how free surface energy (expressed in relative not 

 absolute units) varies during the passage of a solid particle of radius 0.25, inside 



a hypothetical cell of radius 1.0, for various values of — where n and m represent 



n 



the gain in free surface energy caused by a given increase in the area of the cell 



plasma and cell glass interfaces respectively. Abscissae, y, vary with the position 



of the particle with respect to the cell, half inside at 0.22y and completely inside 



at 0.5y. Points marked by large circles are points of equilibrium where surface 



energy is at a minimum, and represent also positions of cell and particle where 



the values of m and n used in calculating that curve would be in equilibrium at 



the angle of contact. The curves are dotted beyond these points to indicate 



that work must be done upon the particle to complete its ingestion since the 



surface energy is increasing. Values of = cos A are given in Table I. See 



text for further discussion. 



