Fossil and Recent Infuso7^ia. 371 



Art. XXI. — Communication respecting Fossil and Recent Infu- 

 soria tnade to the British Association at Newcastle. By Prof. 

 Ehrenberg.* 



To the Editors of the Annals of Natural History. 



Gentlemen^ — You will much oblige me by inserting the sub- 

 joined notice, which has been occasioned by the erroneous report 

 in the Athenasum of the statement made by me at the late Meet- 

 ing of the British Association in Newcastle, in the section of 

 botany and zoology, which statements, so far as I can recollect, 

 were to the following import : 



For the purpose of physiological inquiries I have occupied my- 

 self with the investigation of microscopic organized beings, not 

 only in Europe, but also upon several voyages for several years 

 in other quarters of the globe. The results of my observations 

 had been hitherto scattered in single memoirs, published in the 

 Acts of the Royal Academy of Berlin. Within these few weeks, 

 however, my large work on this subject has been completed,! 

 which consists of a thick folio volume of text and 64 folio copper 

 plates, in which I have endeavored to bring together the whole 

 of our present knowledge of microscopic beings, with their his- 

 tory 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' 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 sec- 

 tion to the importance of the observation of microscopic beings, as a 

 highly influential zoologico-botanical subject, and exhibited earths 

 which were entirely formed of the shields of some Infusoria, I 

 mentioned the eatable infusorial earth from Lillhaggsjon in Swe- 

 den, from Finland, and from Kliecken near Dessau, where they 

 occur in great natural layers ; I stated that the greatest layer 



* From the Annals of Natural History, No. 3, p. 121, London. 

 t Uber Infusionsthierchen, mit einem Atlas von vier und seclizig Kiipfertafeln. 

 Von Christian Gottfried Ehrenberg. 



