PHYSIOLOGY AND PATHOLOGY. 247
saliva through violent rage: this last even to the degree, that an excessively irritated dog may communicate hydrophobia by its bite without being itself affected with rabies or even then contracting the disease, and the same is also asserted of cats and of cocks. The organism is further deeply undermined by lasting grief, and may be mortally affected by fright as well as by sudden joy. On the other hand, all those inner processes and changes which only have to do with the intellect and do not concern the will, however great may be their importance, remain without influence upon the machinery of the organism, with the one exception, that mental activity, prolonged to excess, fatigues and gradually exhausts the brain and finally under mines the organism. This again confirms the fact that the intellect is of a secondary character, and merely the organic function of a single part, a product of life; not the inner most kernel of our being, not the thing–in–itself, not metaphysical, incorporeal, eternal, like the will: the will never tires, never grows old, never learns, never improves by practice, is in infancy what it is in old age, eternally one and the same, and its character in each individual is unchangeable. Being essential moreover, it is likewise immutable, and therefore exists in animals as it does in us; for it does not, like the intellect, depend upon the perfection of the organisation, but is in every essential respect in all animals the same thing which we know so intimately. Accordingly animals have all the feelings which belong to man: joy, grief, fear, anger, love, hate, desire, envy, &c. &c. The great difference between man and the brute creation consists exclusively in the degrees of perfection of the in tellect. This however is leading us too far from our subject, so I refer my readers to my chief work, vol. ii. chap. 19, Fact 2.
After the cogent reasons just given in favour of the primary agent in the inward machinery of the organism
