great changes of the globe's surface were referred to the Noachic deluge, and the fossil remains of animals and vegetables were thought to be whimsical exhibitions of the plastic forces of nature, and not recognized as " Medals of Creation," "Autographs of Time," veritable memorials of ages and cycles that have passed away. The history of the earth's surface, as traced by geology, is the narration of ceaseless change. Slow may be the process by which continents are formed and upheaved; almost infinitely gradual the operation of forces by which mountains are taken to pieces, or by which oceans are poured out like wine from the great earth-cups in which they have so long glittered and reposed; but these alterations go on without rest or stay, and the philosopher exclaims with the poet,

"There rolls the deep where grew the tree!
Oh! Earth, what changes thou hast seen!
There where the long street roars hath been
The stillness of the central sea.

"The hills are shadows, and they flow
From form to form, and nothing stands:

They melt like mists the solid lands,

Like clouds they shape themselves and go."*

But all these changes have taken place under the regulations of definite law," the same yesterday,

Tennyson. In Memoriam.'

to-day, and for ever;" and whether the alteration has been the fall of a grain of sand, or the evolution of all Asia and the Himalayas, to every force engaged in the process has been assigned a direction and a boundary, and, as man's religious faculties lead him to believe, an ultimate object beneficent and sublime.

Modern natural history, based upon transcendental anatomy and physiology, has also confirmed the belief in pervading law. According to this science, groups of animals and vegetables are formed after certain types or patterns, and the several organs constituting a living whole may be traced from their simplest to their highest forms. No individual stands alone; but all are portions of a cosmical or harmonious whole, not so much links of a chain, as hieroglyphic letters of an inspired page, or portions of a creation mosaic, designed and put together upon definite principles which human genius is too glad to imitate, and which prove nature to be what old writers declared it, the "Art of God."

But, for the development of social science it was necessary that man should trace and believe in the operation of law, not only exerting its powers over the physical atoms of the universe, or in the structure of living bodies, but also in the higher

regions of morals and thought. It was also necessary that certain superstitious ideas of inscrutable mystery attending the ways of Providence should be cast aside, and that human faculties should feel that they were welcome worshippers, and not intruders, in any empyrean heights, or Divine council chambers, to which their utmost exertions enabled them to soar. The growth of sanitary science, founded by a living man-Dr. Southwood Smith-has bridged over some of the difficulties between the physical and metaphysical worlds, and questions of life and death that were formerly supposed to belong to theological regions accessible to man's prayers, but for ever excluded from his control, are now found to lie within the domain of his reason, and within certain limits to yield obedience to his will.

In one of his sonnets, Drummond of Hawthornden gives a grand picture of the theological state of mind as opposed to the scientific, and which sanitary science has perhaps done more than anything to change: the words in italics represent the dread of free inquiry that characterized superstitious times, and still lingers in superstitious minds :

"Beneath a sable veil, and shadows deep,
Of inaccessible and dimming light,

In silence, ebon clouds more black than night,
The world's great mind his secrets hid doth keep:

Through those thick mists when any mortal wight
Aspires with halting pace and eyes that weep,
To pry, and in his mysteries to creep,

With thunders, he, and lightnings blasts their sight."

Sanitary science has, as we shall show, done much to encourage wiser views. The religious philosopher is not afraid of "prying into secrets;' he expects no "lightnings" to "blast his sight;" he gazes steadily and fearlessly, and if he meets with "ebon clouds," they do not appal him, but may lead him to exclaim with the Sidney Psalms,

"With day unmask'd my night shall be;
For night is day, and darkness light-
Oh, Father of all lights! to thee."

Within very wide limits the ascertainment of a law is the acquisition of power to control or modify results; and this principle is strikingly exemplified in the history of epidemic diseases, that were at one time regarded as special instruments of Divine wrath, but which are now known to be no more than the poisonous effects exerted by substances formed during certain stages of organic decomposition. In the fourteenth century, when the habits of the most civilized countries were far from cleanly, the conditions necessary for the production of these diseases were abundantly provided, and accordingly a pestilence, known as the "Black Death," de

stroyed one quarter the population of Europe, and one half the population of England. The gradual improvement of manners led unconsciously to a greater obedience to the laws of health, and the virulence of plagues was mitigated: at last these laws were expounded, and in favoured countries and districts the obedience to them became more perfect, and with the happiest results, so that Southwood Smith tells us "the salubrity of London in the nineteenth century and of London in the seventeenth century, is far greater than the difference between London in an ordinary season and in cholera."

There can be no doubt that by the appliances of science and civilization man has added very considerably to the average duration of life, and that he can, at will, remove conditions that are essential to the generation of the most afflictive diseases, and may expect to arrive at a state in which the "slow necessity of death" will be robbed of its terrors, because deprived of its pains. If any one had been told a few years ago that diseases might be grown in rotation, like agricultural crops, or entirely suppressed, the notion would have been repudiated as visionary or blasphemous, according to the character of the objector; and yet we can now appeal to facts in proof of the accuracy of