252 Dr. Wagner on the Structure and 



as well from other green Infusoria. Another animaloule seen 

 in considerable quantity was the Volvoa; glohator of different 

 sizes. On the 27th October the green mass of dead infusoria 

 was still present, and formed a pulverulent layer on the side of 

 the glass turned towards the light. On the surface there was a 

 pellicle which exhibited numbers of the Keroiie pustulata of y" 

 in size. Some had a transverse fissure, as figured by Ehren- 

 berg ; and there were a few examples of Vorticella larva, Miil- 

 ler. On the 3d November, not only the Euglena, but also 

 the Kerone pustulata, had entirely disappeared. A new set of 

 organisms had sprung up; the dead EuglencB still retained their 

 green colour and rounded form, and lay on the sides of the 

 glass ; many of the green masses, however, had become brown 

 and yellow, and had aggregated together. Here and there I saw 

 a ParamcEcmm, and more commonly the Vorticella larva, the 

 interior of which was filled with dead Euglena. There were 

 also a few of the Hydatina senta. The Vorticella larva gra- 

 dually disappeared as the Hydatina increased ; and the latter at 

 last vanished, so that, on the lOth November, the water was 

 quite destitute of infusoria. Similar successions, though not in 

 the particular order of this example, I have seen on different 

 occasions. At other times I have observed several infusoria co- 

 temporaneously existing together, as the Monas, Vorticella, 

 TracJteliu^, Kolpoda, Kerone, Paramcecium^ all of which disap- 

 peared at once. Certainly these transient swarms of living be- 

 ings within the compass of a single glass, is an object of very 

 great interest. We are quite ignorant of its cause. At first 

 sight it might seem to favour the idea of \he generatio equivoca, 

 but my belief in this hypothesis has been pretty well shaken by 

 Ehrenberg's numerous observations, as well as by the few which 

 I have been able to institute in the course of a single summer. 

 Nowhere in nature do we see any animal arrive at once at its 

 perfect state ; there is always a sort of dormant state previous 

 to their properly independent existence. The invisible ani- 

 mating power of the Creator every where in animated nature at- 

 taches itself to the state of the egg, and at this state of existence 

 more especially, does he seem to breathe into living beings the 

 breath of life. The dormant state of the ovum seems to be the 

 transition from the empire of mind to that of matter. The old 



