There is as much danger of hurtiag the brain by idleness as by overwork, according to Dr. Farquharson's theory, as ke gives it in the Popular Science Monthly. Ho argnes that intollectual power ia lessened by the listlessness in which the well-to-do classes generally spend their lives. Under sueh conditions the brain gradually loses itehealth, and, altliough equal to the'demands of a routine existenco, is unable to withstand the Rtraia of sudden emcrgency. So, wheu a load of work is unexpectedly thrown on it in its unprepared state, the worst consequences of what may be cnllcd overwerk show thomselves. Öimilarly, a mifh accustomed to sedontary pursuits is liable to be physically injured by taking suddenly to violent exercise. As to the amount of mental work that may safely be done, Dr. Farquhcrson says "tío long as a brainworkcr is allo to sleep wel), to eat weU, and to take a fair proportion of ontdoor exercise, it may safely be said that it is not nece8sary to iuipose any special limita on the' actual nnmber of hours which he diivotes to hia labors. But when what ia generally known as worry steps in to complioate matters, when cares connected with family arrange inents, or with those numerous persona details which we can seldom oscape, in tervene; or when the daily occupation of life is in itself a fertile sonree of anx iety, then re find one or other of thes three safeguards broken down."