1885.] The Relations of Mind and Matter. 539 
All the numerous products made by man, his clothing, habita- 
tion, tools, &c., and all the changes in the conditions of nature 
produced by his agency, are results of this third phase of evolu- 
tion. Functional change is forced upon the external world, and 
to that extent ceases to act upon the body. Harmonious adapta- 
tion continues necessary, but nature is made to adapt itself to 
man, and man has little need to adapt himself to nature. It is 
not, however, a simple reaction, through the body, of external 
forces upon external nature. A reaction of this kind exists 
throughout organic life. Every motion of an organism in direct 
response to the impulse of external influence exerts an influence 
upon external nature. But asa rule it produces no new condi- 
tions. Adaptation is mainly confined to the body. In psychical 
action, however, new conditions are produced. The energies 
which have flowed into the cerebral reservoir are there recombined 
into new aggregates, or ideas, as we name them. These, in their 
reaction upon external nature, produce new conditions, embodi- 
ments in matter of new relations of energy, and the substances 
external to the body are forced to adapt themselves to the needs 
of the organism. 
This psychical reaction upon external nature is not a common 
characteristic of animal action. It is specially active in man, and 
presents a considerable activity in some of the lower tribes, as 
the beavers, the ants and the bees. But in the great majority of 
animals it is almost non-existent. Very few even of the higher 
vertebrates make any effort to adapt nature to their needs, but 
accept existing conditions. In such cases all the molding action 
of energies must be exerted upon their bodies, and such adapta- 
tion as becomes necessary must be confined to the organism. 
Yet psychical action in these lower animals is not without its 
special results, distinct from those yielded by the direct action of 
external energies, It yields rapid variations in the habits of the 
animal, adapted to particular cases, and which often enable it to 
survive where otherwise it would perish. These may be special 
movements in flight or combat, new modes of concealment, the 
display of cunning in non-habitual manners, and the like. In 
fact, in the difficulty of deciding whether any animal is influenced 
by mental energies or not, we are in great measure dependent 
on the occurrence of unusual actions, adapted to special situa- 
tions. If actions are habitual they may be unattended by con- 
