An interesting paper was read at the last meeting of
the Royal Society on "Experimental Researches on the Temperature of the Head," in which the writer, Dr. Lombard, showed that mental activity will at once raise the temperature of the head, and that merely to excite the attention has the same effect, in a less degree. This is a curious result, as appearing to show that anything of the nature of volition involves a waste of nerve-tissue which is not involved in involuntarily perception and observation. There is no difference, we believe, between the temperature of the sleeping body and that of the waking body, or between that of the waking body and of the head, so long as no act of effort is involved. But if even the least intellectual effort raises the temperature of the head above that which it reaches in amused and idle observation, it would seem to show that there is a waste involved in volition which belongs to no so-called 'automatic' action of the mind. And that is itself a fact of no slight significance.