Page:Popular Science Monthly Volume 46.djvu/749

Rh unable to fix his attention any longer on his work, lapsing into a state of apathy and mental inertia, disappointed at himself and at his failure of interest, but incapable of arousing himself to effort. This is not laziness—it is an inherent mental defect.

Again, there is a type of mind which seems deficient only in the perception of the true relation between events and actions. These people are the victims of their fancies. They are constantly originating most impracticable undertakings. They expend their energy in devising and attempting to carry out the most useless, absurd, and extravagant schemes—sometimes selfish, sometimes apparently philanthropic. They appear to ignore or else can not appreciate the force of common-sense objections, or the reality of insuperable obstacles to their projects; and, finally, if they are defeated, they never blame themselves, but either complain of the lack of human sympathy, or become the victims of a delusion that they are the objects of a conspiracy by enemies whose existence is purely imaginary. The patent office contains a striking museum of such hopeless and visionary schemes and inventions.

It is impossible in the study of defective minds to draw any sharp lines between different individuals; and we can not help feeling that between the man of giant intellect on the one hand, and the speechless idiot on the other, there is an unbroken line of descent, and every possible variety of mental defect.

It is in some of these degenerate brains that we find some of the strangest curiosities of thinking, and some of those extraordinary developments in one line of mental capacity with a corresponding suppression of all other lines. One has only to think of such an individual as "Blind Tom," the pianist, who was a genius in music, able without instruction to reproduce upon the piano with marvelous elaboration of harmony almost anything musical which he had heard, and yet who was almost a brute so far as his moral nature was concerned, and almost an idiot so far as his intellectual powers could be measured. We might also cite a remarkable person recently seen in New York, "Inaudi," who, though until the age of twenty unable to read or write, because too stupid to learn, and manifestly defective in mental capacity, has a power of mathematical calculation which is most extraordinary and inexplicable. The most abstruse problems m arithmetic, such as cubes of numbers in four figures, or a square root of figures in millions, it takes him but a few seconds to solve and this he has been able to do ever since a little boy, without being able at all to explain his methods of doing it. He is as accurate as a calculating machine (and just about as intelligent on other subjects). He relates his history as follows: