431 Bibliographical Notices. 



grains of the same species were derived, according to the varying 

 momenta, Monas Termo, M.vivipara, Astasia, or Colpoda Cucullus, &c. 



Kutzing's observations indeed do not profess to go quite so far as 

 this, but they are scarcely less extraordinary. His views are detailed 

 at very great length, with numerous illustrations, in his prize essay, 

 entitled ' Die Umwandlung niederer Algen-Formen in hohere so wie 

 auch in Gattungen ganz verschiedener Familien und Klassen hoherer 

 Cryptogamen mit zelligem Bau,' published at Haarlem in 1841. The 

 object of this was to show, as the title expresses, that the lower 

 forms of Algse are capable of being changed into more highly orga- 

 nized species, or even into species belonging to different families and 

 classes of the higher cellular plants. And in the present treatise he 

 extends his observations to Infusoria, believing that he has observed 

 their transmutation into Algse. In both cases the subject has been 

 worked out with such pains, and so many valuable observations are 

 intermixed with his peculiar views, that the treatises are worth read- 

 ing, not merely with a view of ascertaining the exact notions enter- 

 tained upon such subjects, but for the sake of the pearls which may 

 be picked up by the way. 



The observations do not admit of abridgement, one depending so 

 much upon another, that it is almost impossible to form any fair 

 judgement without examining the whole ; nor would they be well un- 

 derstood without the aid of the figures, which are executed with the 

 usual skill of the author. 



We shall therefore content ourselves with referring those who are 

 desirous of the latest information on the subject to the memoirs 

 themselves, after making two or three remarks on the matter gene- 

 rally. As far then as we understand what we have read on the sub- 

 ject, we cannot help first remarking that the observations cannot be 

 considered conclusive, apart from all prejudice either way, till a cer- 

 tain number of bodies ascertained to be precisely of the same nature 

 be isolated, and the changes of these observed with every possible 

 precaution to avoid error. At present it seems to us that there is 

 not by any means sufficient proof that the objects in question really 

 arise from germs of the same nature. 



The second remark we would make is, that there appears too often 

 in treatises of this description to be great indistinctness as to the 

 notion of what a species really is. We know that in the course of 

 development higher bodies go through a vast variety of phases which 

 resemble very closely true substantial species which have arrived at 

 their full development ; but we are not therefore to suppose, that in 

 passing through their phases the production has really consisted of 

 such a number of real species. In the Agardhian sense this may be 

 true enough, for when he pronounces the vessels and cells of phae- 

 nogamous plants to be Algee, his meaning appears to be, however 

 strongly he expresses himself, merely that they are representatives 

 of Alga?, and resemble them in structure. 



We would remark also, that the real difficulty of the case does not 

 depend on the question as to the difference of animal and vegetable 

 life. These evidently in certain parts of the creation are so intimately 



