THE PROBLEM OF PATTERN 15 



vacuole appears, and since the processes going on in 

 and about the food vacuole are different from those in the 

 other regions transportative correlation between the vacu- 

 ole and other parts becomes possible. For the appear- 

 ance of this particular nutritional pattern in the 

 Amoeba the external factor, the food, is the directly 

 determining condition, the pattern arising from the 

 reaction of the protoplasm to the food. Similarly, if 

 one portion of the surface of the cell mass is exposed to 

 an adequate oxygen supply while other portions are not 

 so exposed, a regional difference in rate of oxidative 

 activity may arise which may make possible transporta- 

 tive as well as transmissive correlation. Of course 

 organismic pattern in general arises, not in such purely 

 fortuitous manner, but in some very definite and con- 

 stant way for each form, but there seems to be no 

 escape from the conclusion that transportative correla- 

 tion is possible only when such pattern is already present, 

 however it may have arisen. 



The correlative factors of the third group, the 

 dynamic or transmissive factors, consist in the trans- 

 mission through protoplasm or along limiting surfaces 

 of a dynamic change of some sort which is initiated in 

 some particular region. While these factors may 

 involve transportation of electrons or ions from one 

 point to another, they differ from the transportative 

 factors in that the correlative action of one part upon 

 another is accomplished, not by the mass transportation 

 of substance from one to the other, but by the passage 

 of an energetic change which we call excitation or of 

 some dynamic effect of excitation. Capacity for trans- 

 mission of excitation is, so far as we know, characteristic 



