122 Prof. Ehrenberg on Fossil and Recent Infusoria, 



pleted*,which consists of a thick folio volume of text and 64 folio 

 copper plates, in which I have endeavoured to bring together 

 the whole of our present knowledge of microscopical beings, 

 with their history in as complete a state as possible. This book, 

 which I had the pleasure of laying before the section, is not 

 (as stated) the first volume of a work, but complete and entire 

 in itself, and is now in the booksellers 5 hands. It contains 

 drawings of all the 722 species observed by me up to 1835. 

 It is however merely a first essay on this highly interesting 

 and at present inexhaustible subject. I then in a few words 

 directed the attention of the section to the importance of the 

 observation of microscopic beings, as a highly influential zoolo- 

 gico-botanical subject, and exhibited earths which were en- 

 tirely formed of the shields of some Infusoria. I mentioned 

 the eatable infusorial earth from Lillhaggsjon in Sweden, from 

 Finland, and from Kliecken near Dessau, where they occur 

 in great natural layers. I stated that the greatest layer hitherto 

 discovered was to the height of above 28 feet near Lunebourg ; 

 that however similar layers have already been found in Africa, 

 Asia, and the South Sea Islands. At the same time I noticed 

 that I had succeeded in artificially preparing from still exist- 

 ing Infusoria very considerable quantities of earth. I exhibited 

 a large glass full of such artificial siliceous earth, in which the 

 microscope, however, still evidently and distinctly discovers 

 all the forms of the Infusoria constituting it, pounds and tons 

 of which earth may easily be prepared. I mentioned in few 

 words the still existing controversy between botanists and 

 zoologists, both of whom would class in their catalogues these 

 microscopic living forms ; and I briefly noticed the reasons 

 given in detail in my work for each opinion, deciding myself 

 in favour of their being animals. 



I also said a few words on the luminosity of the sea, which 

 subject in part stands in immediate connexion with these mi- 

 croscopic animals, it being regarded an act of animal life ; and 

 I invited attention to the fact that the luminosity in Infusoria 

 and Annulata is an evident voluntary production of sparks, so 

 that in the latter there originates a light apparently conti- 

 nuous or tranquil to the naked eye, from numerous micro- 



* Ueber Infusionsthierchcn, mit einem Atlas von vier und sechzig Kup- 

 fertafeln. Von Christian Gottfried Ehrenberg. 



