288 Philosophy of Botany. 



inal received a certain measure of intelligence, just sufficient 

 for its protection and maintenance. The latter opinion we find 

 plainest expressed in the works of Thomas ab Aquina, a 

 mediaeval saint and celebrated doctor of "theology, and inler- 

 preter of the works of Aristotle. 



It is generally believed that instincts are infallible guides of 

 action. This is, however, far from 'being true to its full ex- 

 tent. They often lead to great injury to the individual, and 

 even destruction of large masses. They are sufficient only for 

 the maintenance of the species in the lower orders, who dis- 

 pose of an immense reproductivity. A phase of selective ac- 

 tion, the germ of reason, is, as above mooted, traceable very 

 ■tarly in the course of evolution. A similar relation is manifest 

 also in the unconscious (not instinctive) actions of man. The 

 execution of, for instance, a sonata rriay pass on in a dormant 

 state of reason, as far as memory of melody, but the expression 

 ■of pathos or affection must be rendered in full consciousness or 

 the performance will be a failure. 



Of instincts there are innumerable varieties — as many, in- 

 deed, as there are species of animals. All may be distinguished 

 on two fundamental principles, as primary and secondary. 



Primary instincts are the general lower impulses, which 

 irom the beginning of organic life existed in the unconscious 

 state of the " psychoplasma " as inherent qualities — self-pres- 

 ervation (protection arid nutrition), and propagation (coitus 

 and rearing of the young). These two fundamental motors 

 of organic life, hunger and love, have originated uncon- 

 sciously, without the access of reason or intelligence, but have 

 afterwards, in the course of evolution, by man and the higher 

 animals become objects of consciousness. 



A reverse relation governs the' secondary instincts. These 

 "have primarily come about by intelligent adaptation, by 

 rational thinking and reflection, and by appropriate conscious 

 action. Gradually they became habitual and unconsciously 

 effective, and appear now in the descendants through inher- 

 itance as congenital qualities. 



The first authorities in physiology and animal psychology 

 bave now arrived at the nearly uniform agreement that 

 there is no qualitative, but only a quantitative, difference be- 



