3i6 POPULAR SCIENCE MONTHLY. 



philosophy, especially in regard to the doctrine of the metamor- 

 phosis of plants. Furthermore, he succeeded in establishing the 

 principles of anatomy so clearly that a rational system of mor- 

 phology became possible for the first time. So important and 

 basal were his demonstrations concerning the real nature of the 

 primordial utricle that by many botanists he is said to have dis- 

 covered protoplasm (1846). Von Mohl, with Schlechtendal, estab- 

 lished the Botanisclie Zeitu7ig in 1842. The list of his works in- 

 cludes ninety titles, embracing subjects in every department of 

 the science. During his administration at Tubingen the garden 

 was enlarged by three additions, to its present dimensions, occu- 

 pying an irregular tract of land on both banks of the Ammer ; 

 important additions were made to the glass houses in the garden, 

 and the institute building was erected in 1846, Perhaps no greater 

 tribute can be paid to von Mohl's broad conception of the scope 

 and needs of botany than the fact that this institute building 

 erected fifty years ago, remains practically unaltered to the pres- 

 ent day, and is still found fairly available for the purposes of 

 modern investigation. 



Upon the death of von Mohl, in 1873, he was succeeded by 

 Hofmeister, who died after having held the post but five years. 

 Hofmeister had perhaps accomplished his more important results 

 before his stay at Tubingen. Like von Mohl, he used an induc- 

 tive method of investigation, and he as well made enormous con- 

 tributions to the material facts upon which many of our present 

 generalizations in morphology rest. The results of the investi- 

 gations published in his Vergleichende Untersuchungen in 1849 

 remain to-day superior to anything achieved in descriptive botany. 

 To Hofmeister must be ascribed, among other important embryo- 

 logical results, the discovery of the alternation of generations in 

 plants, and by the use of his phylogenetic mode of study the ideas 

 concerning natural affinities of the groups of cryptogams and 

 phanerogams underwent an almost total alteration. His estab- 

 lishment of the genetic relationship of these great subdivisions 

 resulted in the overthrow of the prevailing belief in the con- 

 stancy of species. 



Prof. Simon Schwendener succeeded Hofmeister as director of 

 the institute and garden in 1877. He, as well as his two successors, 

 are still in the midst of active work, and it is by no means easy to 

 forecast the final value of the results of their investigations upon 

 the development of the subject. Schwendener has made very 

 important contributions to the biology of lichens, phyllotaxis, 

 besides a long series of contributions of the first rank in the do- 

 main of morphology and physiology. Among these his Mechan- 

 ische Princip in der Bau der Monocotylen is of the greatest im- 

 portance. Schwendener remained but a year at Tubingen, going 



