Chap, hi.] of Cell-membrane in Plants. 295 



where new views opened before him as a result of his exact 

 observation, he cautiously restrained himself and was generally 

 content to hint at matters which bolder thinkers afterwards pro- 

 ceeded to investigate ; such a case occurred in his examination 

 of cell-membranes by polarised light. Hence we miss to some 

 extent the freer flight of imaginative genius in von Mohl's 

 scientific labours; but there is more than sufficient compensation 

 for this want in the sure and firm footing which he offers to the 

 reader of his works ; if we pass from the study of the writings 

 of phytotomists before 1844 to those of von Mohl, we are sensible 

 of one predominant impression, that of security ; we have the 

 feeling that the observer must have seen correctly because the 

 account which he gives of the matter before us seems so 

 thoroughly natural and almost necessarily true, and all the 

 more because he himself notices all possible doubts, and lets 

 those which he cannot remove remain as doubts. In these 

 points von Mohl's style resembles that of Moldenhawer, but in 

 von Mohl it attains to a mastery which is wanting in the other. 



There is an evident connection between von Mohl's dislike of 

 far-reaching abstractions and philosophic speculation on the 

 results of observation and the fact, that in the course of more 

 than forty years' unintermitted application to phytotomy he 

 never composed a connected general account of his subject. 

 His efforts as a writer were confined to monographs usually 

 connected w r ith questions of the day or suggested by the state 

 of the literature. In these he collected all that had been 

 published on some point, examined it critically, and ended by 

 getting at the heart of the question, which he then endeavoured 

 to answer from his own observations. 



For the purpose of these observations he looked about in 

 every case for the most suitable objects for examination, a 

 point to which former phytotomists, with the exception of 

 Moldenhawer, had paid little attention; he then studied these 

 objects thoroughly, and thus prepared the way for the examin- 

 ation of others, which presented greater difficulties. Every 



