iv TRANSLATOR'S INTRODUCTION. 



although independent of reason, volition, and even consciousness, 

 were equally characterised by their intelligent and exact adap- 

 tation to the wants of the animal. To explain the origin of 

 these adapted acts, and to determine their relations to those 

 of the reason and will, was a problem which had occupied and 

 baffled the greatest intellects, from Plato downwards, and a 

 satisfactory solution had never been given to the world. In 

 the theory of Aristotle, these various actions were considered 

 to result from the operation of a sentient, or intelligent 

 principle, endowed with certain faculties or powers. All the 

 faculties that, according to this theory, can exist in a living 

 creature, are five: — namely; 1, the faculty of receiving nu- 

 triment ; 2, of sensation ; 3, of motion in place ; 4, of impulse 

 or desire ; 5, of intelligence : so that soul, considered as 

 endowed with only the nutritive faculty (which is present in 

 all beings), may be attributed to vegetables. The soul of man 

 differs from the soul of lower beings, in being endowed with the 

 faculty of intelligence, in addition to all the others ; consequently 

 it may be considered as containing three portions, — logically, 

 not materially, separated, — one, absolutely without reason ; 

 a second, rational ; a third, participant of reason. 



The Aristotelian philosophy was long exclusively current in 

 the universities and schools ; but, with the revival of anatomy 

 and physiology, the outlines of various systems oi physiological 

 metaphysics appeared, and anatomy, physiology, and natural 

 philosophy, were brought into direct relation with psychology. 

 Our own Willis took the lead in this new department of medical 

 science. He illustrated the human and comparative anatomy 

 of the brain and nervous systems, by drawings and copper- 

 plates ; he distinguished two kinds of souls, namely, the corporeal 

 or sensitive (the anima — the soul of brutes), and the rational 

 or intellectual (the animus) : and he assigned the cerebrum 

 to the latter, and the cerebellum to the former, the diseases, 

 faculties, and operations of which he treated of specially in his 

 two discourses, ' De Anima Brutorum.'^ The first discourse is 

 physiological, and, in many respects, is the analogue and 

 prototype of Unzer's work ; the second is pathological, and 



* De Anima Brutorum quee Hominis vitalis ac sensitiva est, Exercitationes 

 nvM quarum prior Physiologic a ejus naturam Partes, Potentias, et Affectiones 

 tradit ; altera Pathologica, &c. 



