224 



The Structure of Protoplasm 



Those who have once observed protoplasmic streaming in a Plas- 

 modium will recall the "abnormal", but not unusual, phenomenon 

 that the protoplasm shows when it continues to flow only in one 

 direction for an excessively long period of time. From such "abnor- 

 mal" flow, one would necessarily be led to believe that protoplasmic 

 rhythm is often "disturbed." If one bases one's judgment of the 



TIME IN MINUTES 

 Fig. 10. 



rhythm of protoplasm merely upon the reversal of flowing direction, 

 then one will overlook the following important situation. 



Figure 13 shows a case in which the whole undulating curve is on 

 the -)- side of the zero-ordinate for about 12 ininutes. This means 

 that the motive force is exerted always in the same direction during 

 this tiine (from a to h, Fig. 5) . But nevertheless, the undulating 

 curve strikingly reveals a regular change in the force generated in 

 the protoplasm throughout that time. 



Although Figure 13 represents an extreme case, it is generally 

 noticeable in all the foregoing graphs that the area included within 

 the curve and the zero-ordinate on the -|- side differs from that on the 

 — side. This difference between the + and — side indicates that 

 the motive force is not exerted equally in both directions, but 

 always more in one direction than in the other. Because of this 

 polar nature of the motive force, a plasmodium, were it free to 

 move, would advance by flowing forward a little more each time 

 and not retreating all the way back to its original position when it 

 reverses. 



Let us suppose a smooth line cuts an undulating curve in such 

 a way that the area on the upper side of the line is equal to that on 



