492 THE BEGINNINGS OF LIFE. 



might be to a certain extent mutually convertible. 

 We know that different portions of the same mineral 

 substance in a state of solution may, if their ultimate 

 molecular arrangement becomes affected by exposure 

 to different conditions, aggregate into quite different 

 crystalline forms- and that, having aggregated under 

 one of these forms, they are often capable, under the 

 influence of further changes, of lapsing into another 

 and entirely different crystalline state ^. And similarly, 

 it has also been ascertained that Monads, Actinophrys, 

 Peranemata, Amcxbis, and Fungus-germs frequently pro- 

 ceed from contiguous portions of the same matter, 

 whilst these several forms are, moreover, to a very 

 notable extent interchangeable with one another 2. 

 Again, we have ascertained that many of the Algae, 

 Desmids, Pediastrese, and Diatoms (and probably even 

 many Lichens and Mosses) may proceed from different 

 portions of the same kind of matter, and that such 

 modes of growth are also to a certain extent mutually 

 interchangeable 3. So that, after having discovered that 

 totally different forms of Ciliated Infusoria may arise 

 from contiguous and similar algoid vesicles or other 

 matrices, we have a right to expect that evidence 

 would also be forthcoming as to the convertibility of 

 some of these forms. 



^ See pp. 57 and 82. We have also endeavoured to show that a 

 somewhat similar relationship exists between the primordial living 

 things known as Bacteria, Torulae, Vibriones, &c. (pp. 136-143). 



2 In Chaps, xvii. and xx. 



3 See pp. 412-423, and 441-455. 



