76 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 devel- 

 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. Oniraus, Feltz, and others. 



