contain some grains of early ripening wheat. Planted under 

 certain conditions,, these latter alone will mature, but they 

 will serve as seed for the next crop, which will inherit their 

 characteristics for the most part, and which will be almost 

 entirely early ripening wheat. 



When an apparently new structural adaptation is de- 

 veloped in an organism by a set of new conditions, the pre- 

 sumption is that the organism's capacity for this change of 

 structure was previously resident in the organism, and not 

 that the change was wholly caused by the new condition. 

 The condition was the necessary factor which had to be added 

 to the organism's potential capacity, in order that the adapta- 

 tion should result. An organism may in this way be so 

 adjusted as to respond adaptively to any one of a number of 

 possible conditions which may be mutually exclusive. So when 

 one response is realized, the others may be latent. This 

 is shown by the substitution of hair for wool in the coat of 

 a sheep that is taken to a warmer climate. In the domain 

 of behavior a similar rule is obvious. Here a given stimulus 

 calls forth a particular reaction which is especially fitted to 

 the situation. 



The Vital Manifold 



Organisms living in an environment of changing con- 

 ditions are, for the most part, constantly readjusting them- 

 selves to the change. They avoid bad conditions and seek 

 better. Or, when an unfavorable condition can not be avoided, 

 a change takes place in their structure which makes it pos- 

 sible for them to live in that condition. If, when in a certain 

 medium some metabolic change takes place in them, which 

 to be set right demands some other medium, they seek out 

 that other medium either by trial and error reactions or, fol- 

 lowing certain clues present in their surroundings, by some 

 specially appropriate instinctive or habitual reaction. If we 

 admit that such processes are regulatory, we have made a 

 beginning towards defining regulation. We may further say 

 that it is characteristic of organisms having a certain struc- 



THREE] 



