n equivalent of carbonate of lime separated from
the sea--not necessarily in an amorphous condition, most frequently
under an organic form. The sunshine kept up its work day by day, but
there were demanded myriads of days for the work to be completed. It was
a slow passage from a noxious to a purified atmosphere, and an equally
slow passage from a cold-blooded to a hot-blooded type of life. But the
physical changes were taking place under the control of law, and the
organic transformations were not sudden or arbitrary providential acts.
They were the immediate, the inevitable consequences of the physical
changes, and therefore, like them, the necessary issue of law.

For a more detailed consideration of this subject, I may refer the
reader to Chapters I, II., VII, of the second book of my "Treatise on
Human Physiology," published in 1856.

Is the world, then, governed by law or by providential interventions,
abruptly breaking the proper sequence of events?

To complete our view of this question, we turn finally to what, in one
sense, is the most insignificant, in another the most important, case
that can be considered. Do human societies, in their historic career,
exhibit the marks of a predetermined progress in an unavoidable track?
Is there any evidence that the life of nations is under the control of
immutable law?

May we conclude that, in society, as in the individual man, parts never
spring from nothing, but are evolved or developed from parts that are
already in existence?

If any one should object to or deride the doctrine of the evolution
or successive development of the animated forms which constitute that
unbroken organic chain reaching from the beginning of life on the globe
to the present times, let him reflect that he has himself passed through
modifications the counterpart of those he disputes. For nine months
his type of life was aquatic, and during that time he assumed, in
succession, many distinct but correlated forms. At birth his type of
life became aerial; he began respiring the atmospheric air; new elements
of food were supplied to him; the mode of his nutrition changed; but
as yet he could see nothing, hear nothing, notice nothing. By degrees
conscious existence was assumed; he became aware that there is an
external world. In due time organs adapted to another change of food,
the teeth, appeared, and a change of food ensued. He then passed through
the stages of childhood and youth, his bodi