Chap, hi.] of Cell-membrane in Plants. 285 



investigations between 1828 and 1840, so far from being 

 obsolete, are the sources of our present knowledge, and from 

 them every one must still draw who proposes to cultivate any 

 portion of phytotomy. Meyen's views, in spite of the many 

 investigations which he made himself, are entirely confined 

 within the circle of thought represented by the Gottingen 

 essayists, though in his observations he went beyond them, 

 and even beyond Moldenhawer; but the phytotomical views 

 of these men were from the first no law to von Mohl ; he took up 

 an entirely independent position at once with respect even to 

 MoldenhaAver and Treviranus, though a longer time certainly 

 elapsed before he succeeded in freeing himself wholly from 

 MirbeFs authority. For these reasons, and because Meyen's 

 work was interrupted by his death so early as 1840, while von 

 Mohl aided to advance phytotomy for another thirty years, we 

 will speak first of Meyen's labours in that department. 



Meyen l is remarkable for the extraordinary number of 

 his written productions. In 1826, at the early age of twenty- 

 two, he wrote his treatise ' De primis vitae phenomenis in 

 fluidis ' ; two years later he published researches anatomical 

 and physiological into the contents of vegetable cells, and in 

 1830 appeared his ' Lehrbuch der Phytotomie,' founded on 

 his own investigations in every branch of the subject, with 

 many figures on thirteen copper plates very beautifully executed 

 for the time. His industry as a writer was then interrupted by 

 a voyage round the world made in the years 1830-1832, but 

 was again marvellously productive during the last four years of 

 his life (1836-1840); it is difficult to conceive how he found 



1 Franz Julius Ferdinand Meyen was born at Tilsit in 1804, an( l died as 

 Professor in Berlin in 1840. He applied himself at first to pharmacy and 

 afterwards to medicine, and having taken a degree in 1826 he practised for 

 some years as a physician. In 1830 he set out on a voyage round the world 

 under instructions from A. von Humboldt, and returned in 183a with large 

 collections. He was made Professor in Berlin in 1S34. There is a notice 

 of his life in ' Flora ' of 1845, p. 6 18. 



