280 Examination of the Matured Framework [Bookii. 



But the light must have its attendant shadow, and all his 

 carefulness in observation and cautiousness in judgment 

 did not protect him from one prejudice and its evil conse- 

 quences. After Moldenhawer had isolated the elementary 

 organs by maceration, he had to answer the question how we 

 are to conceive of their firm coherence in the living plant. He 

 came to the conclusion, as did von Mohl,Schacht,and others after 

 them, that there must be some special connecting medium ; but 

 he did not hit upon their idea of a matrix, in which the cells 

 are imbedded, or of a cement which holds them together, but 

 on a much stranger theory, which reminds us at once of Grew's 

 thread-tissue, and like that rests partly on incorrect observ- 

 ations. These were too hastily accepted as the basis of a 

 theory which in its turn interfered with after observations. 

 He thought that the cells and vessels were surrounded and 

 held together by an extremely delicate net-work of fine fibres ; 

 in some cases he really believed that he saw these fibres, and 

 interpreted in this way the thickened bands in the well-known 

 cells of Sphagnum, and still more strangely he appears to have 

 taken the thickened longitudinal and transverse edges of cells 

 and vessels for such threads. The unfavourable impression 

 produced by this theory is necessarily heightened by the fact 

 that he gave the name of cell-tissue, a term long used in a dif- 

 ferent sense, to his fancy-structure of reticulated threads which 

 were to hold the cells and vessels together, while he called the 

 parenchyma itself cellular substance, an expression which for- 

 tunately no one copied, and which certainly contributed at a 

 later time to discredit the great services which Moldenhawer 

 rendered to phytotomy. 



His ' Beitrage zur Anatomie der Pflanzen ' are divided into 

 two portions; the first treats of the parts surrounding the 

 spiral vessels ; the second of the spiral vessels themselves. 



The position and collective form of the component parts of 

 the vascular bundle in the stem of the maize-plant are well 

 described in the first section of the work. It is correctly stated 



