Travers, The Experimental Study of Gases (1901); and vapour density determinations in Lassar-Cohn's Arbeitsmethoden fur organisch-chemische Laboratorien (1901), and Manual of Organic Chemistry (1896), and in H.
(1902); Falck, "Die Bedingungen der Zygotenbildung bei Sporodinia grandis," Cohn's Beitr.
Imp. des Sciences de St-Petersbourg, 7 serie, 36 (1888); Dittrich, "Zur Entwickelungsgeschichte der Helvellineen," Cohn's Beitr.
Cohn's brilliant researches, the chief results of which were published at various periods between 1853 and 1872; Cohn's classification of the bacteria, published in 1872 and extended in 1875, has in fact dominated the study of these organisms almost ever since.
The supposed constancy of forms in Cohn's species and genera received a shock when Lankester in 1873 pointed out that his Bacterium rubescens (since named Beggiatoa roseo-persicina, Zopf) passes through conditions which would have been described by most observers influenced by the current doctrine as so many separate " species " or even " genera," - that in fact forms known as Bacterium, Hicrococcus, Bacillus, Leptothrix, &c., occur as phases in one life-history.
Lausanne (1894); Karsten, " Zur Entwickelungsgeschichte der Gattung Gnetum," Cohn's Beitrage, vi.