Johann, a distinguished German botanist, was born in 1730 at Cronstadt, in Transylvania. He early lost his father, and was obliged to fight his way as he best might through his medical course. This he did manfully and honourably. After graduating at Leipzig he returned home, only to find that it was not lawful for him to practise with a foreign diploma in the Austrian dominions. He then removed to Chemnitz in Saxony; and thence, in 1781, to Leipzig, where he published his great work on the mosses under the title of Fundamentum Historiae Naturalis Muscorum. This work secured him the chair of botany at the university, when it fell vacant in 1789. He held it till his death in 1799. Hedwig was an excellent observer; one of the best, indeed, of last century. In microscopic researches his skill was pre-eminent. Two valuable qualities in an observer he combined in a very unusual degree—memory and keenness of eye-sight. Besides his Fundamentum, he wrote many other scientific works and papers, nearly all bearing on his favourite study, but none of them approaching in value the important work with which his fame is now identified.