THE ORIGIN OF LIFE AND ITS EARLY DEVELOPMENT. 
BY DR. WM. DUNCAN McKIM.* 
The subject of the evening’s lecture may be viewed from two 
very different standpoints. We may search into the causes of 
life and its phenomena, when, at once, we find ourselves closely 
wrapped in mystery, or we may seek to observe the living world 
as it actually is, in which case, by patient study, our vision be¬ 
comes clear, and we find that there is something definite to learn 
and know. 
This evening, let us stand well aloof from mere speculation, 
interesting as this may be, and avoiding the vague and indefinite, 
let us endeavor to trace, in the domain of actual knowledge, the 
simple but wonderful plan manifest in the origin and development 
of vegetable and animal life. 
When we write the biography of a man, or the history of a 
nation’s rise and progress, we grasp our theme more broadly if 
we consider first the previous condition of the environment into 
which the man was born, or amid which the nation had its first 
beginnings: in the same wav, we shall obtain a clearer view of 
our subject, this evening, if we consider, for a few moments, the 
series of changes through which our earth has passed before it 
was in a condition to give origin and support to life. 
Let us, then, go back in thought to the earliest period of which 
the human mind can, with any distinctness, conceive, and ask 
how our world arose—and the solar system to which it belongs. 
The only plausible answer ever given to such a question is that 
presented by the Li nebular theory” of Laplace. The correctness 
of this wonderful hypothesis, in the nature of things, we can never 
hope to establish beyond cavil, for there was no one to witness 
the enactment ol the events supposed, nor is the theory suscepti¬ 
ble of mathematical demonstration ; yet, among scientific men 
generally, the theory is regarded as being probably in close cor¬ 
respondence with the truth, for it alone can explain an important 
series of astronomic facts, and no fact has yet been found to weigh 
against it. 
♦Read before the Society, August 6th, 1SS6. 
