40 - + DIATOMS 
animated nature that are intermediate between the animal 
and vegetable kingdoms. in his novel system the 
Diatomaceze were assigned important rank. ‘The early 
teachers of natural history tcok no cognizance of these 
forms ; nor could they do so, from ignorance that such 
monads were in existence. Whien Linnaeus, in 1753, pub- 
lished his great System of nature, the Protista, for the most 
part, were unknown. After his class Vermes, with both 
candour and humour, Linneus grouped together all less 
known living things than those he had named vermes, and 
put them under the significant caption Chaos. 
Othon F. Muller, a Dane, was perhaps the first 
naturalist who left any record of the Diatomaceze. His 
notice is in his work entitled ‘‘ Animalcula Infusoria,”’ 
written not long before his death in 1784. So recent as 
1825, but fifty species had been fonnd. But Ehrenberg’s 
work, ‘‘ The Infusionsthierchen,’’ printed in 1838,was the 
forerunner of such a new revelation regarding Diatomis, 
and induced so many able men of different countries to 
study them, that by 1860 Rabenhorst in his ‘‘ Freshwater 
Diatomaceze,’’ and in his ‘‘ Conspectus,’’ had recorded 
4,000 species. 
Since the monumentai labor of Rabenhorst workers in 
various parts of the world have more than doubled the 
diatomaceous species known to him. Bailey, H. L. Smith, 
Edwards and others enthusiastically prosecuted the study of 
American Diatoms, an undertaking that was commenced 
by Ehrenberg. Their labours worthily rank with the 
work of William Smith, Kitton and many workers iu 
England ; and with that of Heurck, Schmidt and others on 
the continent. The Rev. Francis Wolle, in his ‘‘ Diatom- 
aceze of North America,’’ published a few years since, 
pointed out that at that date the ‘‘ Diatomacez of the 
World ’’ aggregated 8,000 species. His own work, which 
comprises 112 plates, gives 2,200 illustrations of 1,400 
‘‘North American Diatoms,’’ which are classified in 
