This little treatise though addressed by a physician to human beings, has an equal interest to those who have to care for the health of vegetation. Dr. Moore shows that all zymotic diseases, or those which like scarlet and other fevers, are the result of blood fermentation, can only successfully attack when vital power is weak from defective nutrition. Thus the person properly nourished in all his parts is proof against a disease which may destroy hun-•dreds of his neighbors. Now if we could only tell how to properly nourish ourselves, we should all be proof against disease, but there are some whose powers of applying nutrition are defective from birth, and others whom old age enfeebles; but the conditions of health may be so understood and controlled, that vital power may be aided and assisted to resist zymotic attacks. Dr. Moore shows that external heat is the great enervator or invigorator as the case may be, and he believes that by controlling heat in special cases we can so control nutrition that many now fatal attacks might be rendered inert.

It gives us pleasure to read these results of Dr. Moore's experience with human bodies, because it accords well with our own observations on vegetation, as we have frequently recorded in the Gardener's Monthly. There is a degree of heat to which the roots of trees may not be subjected without injury to their vital powers, and it is because of this that grass or mulch of some kind to keep off the fierce Summer sun's rays, has been found of so much value to the orchardist, - as we pass from the lake regions southwardly, - and it has been noted over and over again that trees not wholly adapted to our climate, always suffer more in those Winters which succeed very hot Summers. Other points might be referred to, but enough has been said to show that life in plants is affected by much the same influences as affect it in the animal world.