"6 NATURE AND LIFE. 
a fixed shape and a special structure. The elements of the 
tissue of plants form in the same way within a mucilagi- 
nous liquid called cambium, and in which the most improved 
instruments detect nothing but shapeless matter. There 
are as many different blastemas as there are tissues; in 
other words, the anatomical elements of each tissue exude 
between them those generative fluids whence similar ele- 
ments spring. We shall presently have occasion to notice 
some interesting instances of this. 
This hatching of living molecules in the mass of blaste- 
ma, proved by Robin’s numberless experiments, confirmed 
by those of many other savants,’ is a true spontaneous 
generation. In fact, organized corpuscles are here deyel- 
oped without germs or parents, in the midst of a liquid in 
which, a few moments earlier, nothing would authorize us 
to foretell their appearance. Only this liquid results from 
a living organism, that is, one whose elementary particles 
are themselves in course of ceaseless molecular renewal. 
Beyond these facts we have not been able to prove abso- 
lutely that beings, even microscopic ones, can be produced 
simply by the concurrence of physico-chemical forces. 
The numerous experiments which have occasioned within 
a few years so hot and passionate controversies, prove 
that a liquid or an infusion observed in the vessels of 
a laboratory remains absolutely barren as long as it is 
guarded from contact with germs and spores conveyed by 
the atmosphere. This result, demonstrated by M. Pasteur, 
demolishes all the arguments called up in support of hete- 
rogenesis. 
The three modes of birth that we have just examined 
are the very modes of generation of living beings, since 
these invariably begin by anatomical elements. To give a 
clearer idea of these very curious operations of Nature, let 
us see what takes place in the organized granule which is 
1 See the late works of Messrs. Onimus, Feltz, and others. 

