ORIGIN OF LIFE. 57 
tion of their merits, whilst a closer scrutiny of their 
respective foundations tells much more in favour 
of the new hypothesis of Archebiosis; in the first 
place, because no reason can. be shown why the 
process of life-evolution should have been arrested ; 
and secondly, because if it does occur at the pre- 
sent time, it never could come under the direct 
observation of anybody, and consequently the 
general experience of mankind concerning the 
‘reproduction’ of living things, upon which the 
second hypothesis and the dictum omne vivum 
ex vivo have been founded, would in no way be. 
questioned—the facts would lie altogether outside 
this experience.* 
But a belief in Archebiosis, whether past or present, 
seems to me necessarily to carry with it a belief in 
Heterogenesis. So that if Archebiosis be continually 
taking place, Heterogenesis should be an equally 
common phenomenon. And even for those who 
believe that Archebiosis took place in the past though 
it has now ceased, Heterogenesis would remain as 
a very possible and even probable process from an 
* As I have elsewhere said : —“‘ Living matter, like crystalline matter, 
is only formable by a synthesis of its elements. As crystals have not 
the power of self-multiplication, they have only one mode of origin. 
But because organisms have reproductive powers, the obviousness of 
these modes of increase has sufficed to cast doubts upon the reality 
of the independent origin of living units.”—The Beginnings of Life, 
vol. ii., p. 77 
