190 Transmutation of Form in certain Protozoa. 



My own view of the great question involves what I venture 

 to term the Unity of Kature, that is to say, that so far as our 

 senses will at present carry us, we see no separation of nature's 

 works into classes, except in a very hroacl and rough investigation ; 

 and whatever class we examine, whether of the animal or vegetal 

 kingdom, there are always some members whose characters approach 

 so closely to those which are considered as indicative of another 

 class, that we are perpetually brought face to face with objects 

 which it is impossible to affix the distinct section to which they 

 properly belong. Thus, whether we divide nature into animal, 

 vegetal, and mineral — into organic and inorganic, or the animal 

 world into vertebrate and invertebrate, or the vegetal into endogen, 

 exogen, and cryptogam, or whatever way we choose to divide it, in 

 no case can the boundary line be so drawn as to decide definitely 

 where to place eveiy specimen of nature's products. This is due 

 to the hmits which are drawn around our senses, and in that 

 section of nature to which our attention is at present directed the 

 highest powers of the microscope are unable to reveal to us the 

 smallest of nature's organisms which develop the phenomena of life. 

 Testimony is borne by Dr. Lionel Beale to this efi'ect, and he is 

 understood to make use of the highest powers that have at present 

 been produced. But independent of this extreme minuteness of 

 particles of matter, we have reason to consider it as certain as any- 

 thing we may be said to know, that there is a definite point at 

 which the unit condition of matter commences its existence, and 

 within the limits of these two considerations we seem to arrive 

 at a view of life consistent with law, with harmony, and with what 

 we call " creative wisdom." 



This view, as supported by the principal savans at the Edin- 

 burgh Congress, is in accordance with Harvey's law, " Omne vivum 

 ab ovo." 



In the consideration of the objects to which our attention is 

 directed in the present remarks, we are led only to the contem- 

 plation of them as passing through various stages of growth, and 

 possibly in some cases of transmutation somewhat allied to those 

 imago changes of which the insect class furnish us with such 

 beautiful and instructive examples. In deahng with the further 

 details of the progress of growth from less developed forms we 

 shall have occasion to notice that there is considerable evidence 

 to show that the form in which the Infusoria commence life as 

 independent organisms is not always the same, for there is some 

 reason to believe that considerable development may take place 

 within the parental cavity before the proles is extruded for inde- 

 pendent growth. Although this subject must be deferred for more 

 mature consideration in another paper, yet it may help us to con- 

 template some of the forms which we have now before us with 



