ORIGIN OF LIFE. 51 
Reduced to its simplest form, the fundamental fact 
whose interpretation is doubtful may be thus ex- 
pressed :—Certain of the most minute living things are 
known to appear in some fiuids independently of pre- 
existing visible germs.* In explanation of phenomena 
of this kind, observed by the aid of the microscope 
two hypotheses are offered :— 
(1). The hypothesis of Archebiosis (carrying Hetero- 
genesis with it as a necessary consequence), which 
supposes that these minutest living things have come 
into being, and into the region of the visible, by a 
process of chemical combination and growth, similar 
in kind to that by which crystalline germs originate 
in other fluids. 
(2). The hypothesis of Panspermism (discrediting . 
both Archebiosis and’ Heterogenesis), which supposes 
that the minutest living things above referred to 
have merely developed in the fluids, owing to the 
accidental presence therein of invisible ‘ germs’ 
thrown off from pre-existing living organisms. 
Thus we start with two possibilities which, in the 
eyes of the Evolutionist at least, have about an equal 
amount of probability. Each hypothesis is also 
supported by an analogical argument of considerable 
force. : 
The analogy tending to support the first hypothesis 
* See ‘‘ The Beginnings of Life,” vol. i, pp. 292, ef seg. 
E 2 
