NOTES AND MEMORANDA. 309 



that every sound causes its own particular rod to vibrate, and 

 this rod vibrating, causes the nerve-cells in connection with 

 it to send a nerve-current to the brain. — Nature. 



Death of Von MoM^^ye have to record the death of 

 facile princeps the most eminent of vegetable physiologists. 

 Prof. Hugo von Mohl, which took place on April 1st at 

 Tubingen. Von Mohl was born at Stutgart in 1805, and in 

 1835 was appointed Professor of Botany and director of the 

 Botanic Gardens at Tubingen, a position he has held ever 

 since. Conjointly with Schlechtendal, and since his death 

 with Prof, de Bary, formerly one of his pupils, he has been 

 editor of the weekly ' Botanische Zeitung' since its com- 

 mencement in 1843. He was one of the foreign members of 

 the Linnsean Society, having been elected as long ago as 

 1837. Von Mohl has been a copious and most accurate 

 writer on subjects connected with vegetable anatomy and 

 physiology, of which he may be said to have laid the secure 

 foundation in his early investigations of the true relation of 

 cell-membrane and contents. Among his original observa- 

 tions we may especially mention his essay on the Structure 

 of Endogens, published by von Martins in his ' Historia 

 Palmarunij'and on the Stem-structure of Cycadsinthe "[Vege- 

 table Cell," which appeared in Rudolph Wagner's ' Hand- 

 worlerbuch ;' on the Origin and Structure of Stomates ; on 

 Cuticle; on the Structure of Cell-membrane; on the Struc- 

 ture and Anatomical relation of Chlorophyll ; on the Multi- 

 plication of Plant-cells by division, and numerous other 

 essays collected in his ' Vermischte Schriften.' 



