270 
TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
required for the production of a definite living organism out of 
organic compounds purely chemical. The probability is that the 
compounds so slowly formed, issued just as slowly in the lowest 
form of life at a time when the heat of the earth's surface was 
falling through those ranges of temperature at which the higher 
organic compounds are unstable. But ; the moulding of these 
compounds, by this slow process, into the simplest types, must 
have commenced with portions of Protoplasm (i.e., with making 
portions of Protoplasm) more minute, more indefinite and incon- 
stant in their characters than the lowest speck of Protoplasm 
in the Protista of Haeckel. 2 Professor Huxley virtually agrees 
with the above representation, though he will not commit him- 
self to any definite statement as to mode and duration of 
the process. He states that he has no belief as to the mode in 
which existing forms of life have originated, but that were he 
able to look back "beyond the abyss of geologically-recorded 
time to the still more remote period when the earth was passing 
through physical and chemical conditions which it can no more 
see again than a man can recall his infancy, I should expect to 
be a witness of the evolution of living Protoplasm from non 
living matter." 3 
As an ingenious guess at the origin of Life from purely mechan- 
ical action of ultimate atoms, I may mention a speculation of the 
late Professor Clifford. The question is to explain how living 
matter acquired its peculiarity of producing its like. It may 
have arisen, he says, in a first step in the progress towards the 
development of the actual living molecules. He takes a molecule, 
acetelyne, formed of two carbon atoms and four hydrogen ; and 
from three of these he gets, by an experiment, the molecule known as 
benzene with its six carbon and six hydrogen atoms. When once 
the first step is taken, and the new compound is formed, " it has 
the property of assisting the formation of its like," but "nobody 
knows why. ... It is impossible to disprove the statement" 
that benzene cannot be made out of simpler molecules without 
some few molecules of pre-existing benzene. There is no test 
delicate enough for the disproof. But it is generally held that 
the benzene molecule is formed by the collision of three acetelyne 
molecules in favourable positions; this collision is a coincidence 
2 Principles of Biology, i. pp. 480-482. 
3 Critiques and Addresses, p. 239. 
