The fact that Schizomycetes produce spores appears to have been discovered by Cohn in 1857, though it was expressed dubiously in 1872; these spores had no doubt been observed previously.
In effect the urea first becomes carbonate of ammonia by a simple hydrolysis brought about by bacteria, more and more definitely known since Pasteur, van Tieghem and Cohn first described them.
Pasteur and Cohn also pointed out that putrefaction is but a special case of fermentation, and before 1872 the doctrines of Pasteur were established with respect to Schizomycetes.
In 1876, however, Cohn had seen the spores germinate, and Koch, Brefeld, Pratzmowski, van Tieghem, de Bary and others confirmed the discovery in various species.
Lucknow, where a small British garrison was besieged in the residency, was twice relieved, once temporarily by Sir James Outram and General Havelock, and afterwards permanently, by Sir Cohn Campbell, who had been sent out from England to take the chief command.
He became a frequent contributor to the Monthly Review, the Gentleman's Magazine, the AntiJacobin Review and the British Critic. He also wrote several articles for the third edition of the Encyclopaedia Britannica, and on the death of the editor, Cohn Macfarquhar, in 1793, was engaged to edit the remaining volumes.
As to the constancy of form, however, Cohn maintained certain reservations which have been ignored by some of his followers.
Many of his works will be found in Migne, Patrologia Graeca, cix., cxii., cxiii.; for editions of the rest, C. Krumbacher, Geschichte der byzantinischen Literatur (1897), and the article by Cohn in Pauly-Wissowa's Realencyclopadie der classischen Altertumswissenschaft (1900) should be consulted.
On many grounds Cohn infers a Hebrew original.
Struve published an account of the application of clockwork as an aid in Repsold's method; and, later, Dr Cohn published a more elaborate paper on the same subject in the Astron.