PRE FA CE. 



XI 



"^Uon of 



Tl 



the 



g^nated i 



whereby they are converted into the embryos of 

 large and complex Rotifers. 



Hetero 



n ' livi 



in tie 



ing' 



t 



mode 



by invisible processes, the simplest living units may 

 arise. So that after watching all the steps of the more 

 complex phenomena, we may find it less difficult than 

 we should otherwise have done to believe in the occur- 

 inous kinds of E rence of the simpler process of Archebiosis — more espe- 



'^^ing surface 



n? 



Why 



cially when its occurrence is attested 



facts and 



S now be impo* probabilities of the highest independent value, 

 similar nature Again, we know that simple mineral substances may 



exist in different allotropic conditions, just as numeri- 

 bccn made toji cally-similar combinations of different elements may 



IniK exist in two or more isomeric states. But, if mere 

 tu differences in molecular arrangement may cause sulphur 



:)itrary curtailm 



fortunately that 



3mbi nations, tot 



or 



end 



pre\ 



.'ions 



arsenic, on different occasions, to present wholly 

 different appearances and properties; or if a similar 

 alteration in molecular arrangement may lead such salts 

 ,|. as mercuric iodide to pass easily from one to another 

 • in some new)' ^^^ ^^ crystallization, it should not be very difficult 



able of ocular ^'^ - -- 



al molecules 



ements 



r 



I 



art 



for us 



mi 



-arrang 

 livin 



m 



ft 



(7 

 V 



matter, ^ 

 tot. 



comparative ease, undergo somewhat analogous mole- 

 cular rearrangements, and that 



such changes miglut 

 I the form and other 



rtually ^^^^ attributes of the living aggregate* And now, as matter 



"'' of fact, we have to state that the occurrence of Hetero- 

 genetic Transformations amongst lower living things 





and 



in portions of higher 



living things have 



been 



fn f^^^' 3,nd isomeric modifications amongst different kinds of 



be seen to 



mp 



almost as well attested as the occurrence of allotropic 





not-living matter. 



;t 



