INTRODUCTION TO CRYPTOGAMIC BOTANY. 85 



excuse for the earlier observers, if they made mistakes, aud 

 preconception easily gave rise, mider tlie imperfect magnifiers, 

 some twenty-five years since, to reports of structure which had 

 their existence only in the imagination of the writers. When 

 Dujardin had once called in question, and with great propriety, 

 many of Ehrenberg's observations, with regard to undoubted 

 animalcules, there was not much hazard in doing the same 

 with respect to Diatomacece and Desmidiacece (Fig. 7). 

 A practised observer, with good modern instruments, would 

 now scarcely entertain a doubt upon the subject, when such 

 objects as the eggs of Aplysia and Gnats (Fig. 12), not 

 to mention such Polypidoms as Alcyonidium, are placed 

 before his eyes, though they, and many similar productions, 

 were formerly registered as vegetables. It is true, that in 

 some cases, motion may exist, and that apparently, volun- 

 tary ; but it is now well known that such motion is by no 

 means a certain indication that a given body does not be- 

 long to vegetables. In the article Vaiicheria clavata, of the 

 Gleanings of British Algiie, so long ago as 1833, I drew atten- 

 tion to the possibility of animal and vegetable life existing at 

 different stages of growth in the same individual, and what is 

 stated there, requires but little modification now, even after 

 the discoveries which have since been made respecting zoo- 

 spores and spermatozoids. It is precisely at such osculating 

 points that these complex phenomena may be expected ; and 

 as life, whether animal or vegetable, is only a phrase, formed 

 to express certain phsenomena, the plain fact is, that similar 

 phenomena are exhibited by animals and vegetables, though 

 such phasnomena may be confined to a very small period, 

 compared with the whole range of existence. The degree of 

 volition, if such it may be called, is extremely low, and may 

 be unattended with any consciousness, and merely be the in- 

 dication of certain exigencies of the minute body for light, or 

 Other necessary elemental conditions. When, however, it is said 

 by the German naturalists, that organised matter has a tendency 

 to be converted into organised bodies, a proof is required 

 on the part of the assertors, that every source or possibility of 

 error has been removed, before they can challenge even a state 



