460 PROCEEDINGS OF THE AMERICAN ACADEMY 



response to a prize-question offered by the Tubingen Medical Faculty. 

 In it he divined the real nature of the movements which coiling stems 

 and tendrils execute, as has recently been clearly made out. In the 

 following year appeared his inaugural dissertation on the Pores of the 

 Cellular Tissue of Plants, in which his later views and discoveries, 

 respecting the structure, growth, and component parts of cells, as sub- 

 sequently developed, are already foreshadowed. About this time his 

 choice was made for a scientific rather than a medical career ; and he 

 went to Munich to prosecute more advantageously his favorite studies. 

 Here the late Von Martius and Zuccarini were his botanical masters, 

 and Agassiz, Karl Schimper, Braun, and Engelmann his fellow-students. 

 Here he made those researches upon the anatomy of ferns, cycads, 

 and especially of palms, — the latter a most important contribution to 

 Martius's great work upon palms, the former also contributed to another 

 work by Martius, — which first displayed his remarkable talents for his- 

 tological investigation, to which his subsequent scientific life was mainly 

 devoted. His merits were promptly recognized by a call to the Im- 

 perial Botanic Garden of St. Petersburg, as assistant to its director, 

 Dr. Fischer, and to the chair of physiology in the Academy of Berne. 

 He accepted the latter in 1832, and occupied it until 1835. Then, 

 upon the death of Schubler, he returned to Tiibingen, accepted the 

 professorship of botany in its High School, in which chair and in that 

 of Tubingen University the rest of his life was passed. Invitations to 

 more prominent and lucrative positions, as, for example, to the botanical 

 chair at Berlin University when vacated by the death of the veteran 

 Link, were unhesitatingly declined. Although he published numerous 

 (about ninety) special papers or articles, most of them important and 

 timely, and some of great pith and moment, he resolutely declined to 

 bring out any general work. His Mikrographie (1846) and his 

 " Principles of the Anatomy and Physiology of the Vegetable Cell " are 

 his only writings which may claim to be such. The latter, an admira- 

 ble and still invaluable treatise, appeared as an article in Rudolf Wag- 

 ner's Cyclopaedia of Physiology, but is best known to English readers 

 in its separate form, in a translation made by the late Professor Henfrey, 

 with the author's sanction, issued by Van Voorst in 1852. A year 

 or two later it was for a time understood, to the great satisfaction of 

 botanists, that Mohl had agreed to take a prominent part in the pro- 

 duction of a general Manual of the Anatomy and Physiology of 

 Plants ; but his promise was soon withdrawn. For thirty years he was 



