Geometrical ratio increases rapidly. It is represented by a series 2 × 2 × 2 × 2=16. But the augment by permutation is still greater. This is shown in the series 2 × 3 × 4 × 5=120. Mr. George Iles claims that this is the true rate of modern progress as represented by the effect on the world of printing, steam, electricity, and photography. This is progress “saltatory,” or by leaps. It explains, he believes, the sudden and rapid advance of some periods, and also the losses of continuity sometimes observed. His maxim is: “The newest of the factors of culture multiplies all the factors which went before it.” CHAPTER IV _PATHOLOGICAL VARIATION IN THE ETHNIC MIND_ We have seen in the preceding chapter that atrophy and regression are an essential process of progressive evolution, necessary in order that the preponderance of nutrition may be cast in favour of the most useful organs and structures. This is “physiological” degeneration, “degeneration with compensation,” the result of which is finally favourable to the general economy. But there is another form of degeneration, the tendency of which is distinctly injurious to the organism as a whole, and which, if unchecked, would compass its destruction. This is “pathological degeneration,” “degeneration without compensation.” Although such processes are also biologic,—that is, carried on by life products (cellular neoplasms),—they are incapable of independent existence and are always warring against that of the organism in which they are engendered. It is an axiom that the laws of progressive evolution do not apply to pathological processes (Virchow). In the history of the mental life of individuals and nations we find a striking parallelism to these physical processes, certain degenerations bringing with them compensations in the growth of higher faculties, others tending inevitably to the destruction of the individual or the group. The latter belongs to the domain of “ethnic psycho-pathology.” Psychologists have shunned this field. “Psychology,” says a recent American writer, “must concern itself with the _normal_ mind”; and a German author of merit has insisted that mental pathology has no place in ethnology, because this science occupies itself only with the progress of mankind. Much more correct is the opinion of Dr. Ireland that “it is quite erroneous to treat the history of the human race as that of the sane alone”; and, indeed, we may almost go so far as Professor Capitan, of the School of Anthropology of Paris, and say: “Everybody is diseased. Nobody is healthy. We are obliged to study mankind in a constantly morbid condition of body and mind.” Or we may go as far as Pascal, when he says, “Men are naturally so insane that he is deemed insane who is not insane with the rest.”