As soon, however, as we become in- competent to make this adjustment insanity is established 1.

" These passages exactly describe the condition of a wizard and his tribe afflicted with social paranoia: their theories of magic and animism and of the wizards relations with invisible powers, may truly be said to form an organised body of (false) knowledge, to colour all their lives, to explain everything that happens to them ; and their mistakes and disorders to be incorrigible by reflection or experience.

Such conditions of the social mind have, I believe, existed (and may still exist), tending toward, and sometimes ending in, a tribes destruction.

That, in such a case, there should be unanimity is not necessary; it is enough that the current of belief, in certain directions, be overwhelming.

But such extreme cases are rare.