METEORITES, AND THE ORIGIN OF LIFE. 
391 
acceptable that, tacitly or explicitly, all men discard it. It is 
often assumed that all, and it is certain that some, meteorites 
are fragments severed from larger masses and launched free into 
space. It is as sure that collisions must occur between great 
masses moving through space as it is that ships, steered without 
intelligence directed to prevent collisions, could not cross and re- 
cross the Atlantic for thousands of years with immunity from such 
catastrophes. When two great masses come into collision in 
space it is certain that a large part of each of them is melted ; 
but it appears equally certain that in many cases a large quantity 
of debris must be shot forth in all directions, much of which may 
have been exposed to no greater violence than individual pieces 
of rock experience in a landslip or in blasting by gunpowder. 
Should the time when this earth comes into collision with 
another body, comparable in dimensions to itself, be when it is 
still clothed, as at present, with vegetation, many great and 
small fragments carrying seed and living plants and animals 
would undoubtedly be scattered through space. Hence and 
because we all confidently believe that there are at present, and 
have been from time immemorial, many worlds of life besides 
our own, we must regard it as probable in the highest degree 
that there are countless seed-bearing meteoric stones moving 
about through space. If at the present instant no life existed 
upon this earth, one such stone falling upon it might lead to its 
becoming covered with vegetation. “ I am fully conscious,” he 
concludes, “ of the many scientific objections which may be 
urged against this hypothesis, but I believe them to be all 
answerable. . . . The hypothesis that life originated on 
this earth through moss-grown fragments from the ruins of 
another world may seem wild and visionary ; all I maintain is 
that it is not unscientific.” * 
Sir William Thomson’s views, thus plainly set forth, did not 
fail to attract adverse criticism. Before we proceed to consider 
the comments which his hypothesis called forth, we may call 
the reader’s attention for a short time to speculations in the same 
direction which have appeared in the writings of scientific men 
in France and Grermany. 
First, we must refer to a remarkable passage in the great 
work of Count A. de Bylandt Palstercamp, on the Theory 
of Volcanos. f He wrote in 1835, at a time when Laplace’s 
theory that meteorites were hurled at us from lunar volca- 
noes was still generally received, and this will account to some 
* “ Address of Sir William Thomson, Knt., LL.D., F.R.S., President.” 
London : Taylor and Francis. 1871. P. 27. 
t “Theorie des Volcans. Par le Comte A. de Bylandt Palstercamp.” 
Paris : Levrault. 1838. Tome i. p. 95. 
