470 
and latter part of the seventeenth century, 
the brilliant Stenson, in Italy, and Hooke, 
in our own country, had laid hold of some 
of the problems presented by fossil remains, 
and Woodward, with others, had labored in 
the same field. In the eighteenth century, 
especially in its latter half, men’s minds 
were busy about the physical agencies de- 
termining or modifying the features of the 
earth’s crust; water and fire, subsidence 
from a primeval ocean and transformation 
by outbursts of the central heat, Neptune 
and Pluto, were being appealed to, by Wer- 
ner on the one hand, and by Desmarest on 
the other, in explanation of the earth’s phe- 
nomena. The way was being prepared, the- 
ories and views were abundant, and many 
sound observations had been made; and 
yet the science of geology, properly so 
called, the exact and proved knowledge of 
the successive phases of the world’s life, 
may be said to date from the closing years 
of the eighteenth century. 
In 1783, James Hutton put forward in a 
brief memoir his ‘Theory of the Earth,’ 
which in 1795, two years before his death, 
he expanded into a book; but his ideas 
failed to lay hold of men’s minds until the 
century had passed away, when in 1802, 
they found an able expositor in John Play- 
fair. The very same year that Hutton pub- 
lished his theory, Cuvier came to Paris and 
almost forth with began, with Brongniart, 
his immortal researches into the fossils of 
Paris and its neighborhood. And four 
years later, in the year 1799 itself, William 
Smith’s tabular list of strata and fossils saw 
the light. Itis, I believe, not too much to say 
that out of these geology, as we now know 
it, sprang. It was thus in the closing years 
of the eighteenth century that was begun the 
work which the nineteenth century has car- 
ried forward to such great results. But at 
this time only the select few had grasped 
the truth, and even they only the begin- 
ning of it. Outside a narrow circle the 
SCIENCE. 
[N.S. Von. X. No. 249. 
thoughts, even of the educated, about the 
history of the globe were bounded by the 
story of the Deluge—though the story was. 
often told in a strange fashion—or were 
guided by fantastic views of the plastic 
forces of a sportive Nature. 
In another branch of science, in that 
which deals with the problems presented by 
living beings, the thoughts of men in 1799 
were also very different from the thoughts 
of men to-day. It isa very old quest, the 
quest after the knowledge of the nature of 
living beings, one of the earliest on which 
man set out; for it promised to lead him to 
a knowledge of himself, a promise which 
perhaps is still before us, but the fulfillment 
of which is yet far off. As time has gone 
on, the pursuit of natural knowledge has 
seemed to lead man away from himself into 
the furthermost parts of the universe, and 
into secret workings of Nature in which he 
appears to be of little or no account; and 
his knowledge of the nature of living things, 
and so of his own nature, has advanced 
slowly, waiting till the progress of other 
branches of natural knowledge can bring it 
aid. - Yet in the past hundred years, the 
biologic sciences, as we now call them, have 
marched rapidly onward. _ 
' We may look upon a living body as a 
machine doing work in accordance with 
certain laws, and may seek to trace out the 
working of the inner wheels, how these 
raise up the lifeless dust into living matter, 
and let the living matter fall away again 
into dust, giving out movement and heat. 
Or we may look upon the individual life as 
a link in a long chain, joining something 
which went before to something about to 
come, a chain whose beginning lies hid in 
the farthest past, and may seek to know 
the ties which bind one life to another. As 
we call up to view the long series of living 
forms, living now or flitting like shadows, 
on the screen of the past, we may strive to 
