22 EVOLUTION OF LIFE, 
Let us illustrate by the example of the formation of a 
crystal out of a simple solution. A nucleus first appears, 
then increment after increment is added, according to 
laws, until the crystal is formed. The case of the origin 
of a Monad is a parallel one. We have a solution; in 
this solution appears the Monad. There is no more 
necessity for the pre-existence of a Monad in the solution 
than that there should have been a pre-existing parent 
crystal. In both solutions exist the elements of which 
the Monad and Crystal are formed; the laws according 
to which they are formed are as susceptible of study in 
the one case as in the other. Theoretically, therefore, there 
is no objection to the idea of Spontaneous Generation, the 
laws of which must be investigated as any other mechanical 
problem has been; the problem being a question of the 
redistribution of matter. . In fact, acci Re to the experi- 
ments of Pouchet, Pennetier, Bastian, Wyman, and others, 
Vibrios and Bacteria do appear in solutions where there 
was not previously a trace of these minute beings. 
Want of space prevents us from discussing this question 
in detail. We can only say that at present the evidence 
seems to us in favor of the view that Spontaneous Genera- 
tion takes place at the present day under favorable condi- 
tions. We turn now to the consideration of living Monera 
and Amcebee. Whatever their present or remote origin may 
have been, an Amaba is a Monas with a nucleus. The 
Amcebe probably came originally from Monera, if they are 
not now so produced, and in some cases colonize them- 
selves, forming the Sponge,—this view being sug gested by 
the Yonne of the Sponges, which cannot be ส แก อ ย 7 
from Amoebze,—or the Amoebz gaining tails and hairs, like 
ihe E o gave rise to the Animalcula or Infusoria. 
But as certain Amcebe and Euglena cannot be distinguished 
from the spores or young of the simplest plants, the origin 
of the vegetal world must be sought also in these minute 
