z6o Examination of the Matured Framework [BookH. 



verbal description. The drawing will be perfect in proportion 

 to the practised skill of the eye that observes and of the mind 

 that interprets the forms. The copy should only show to 

 another person what has passed through the mind of the 

 observer, for then only can it serve the purpose of a mutual 

 understanding. There is also another point to be considered ; 

 it is exactly in the process of drawing a microscopic object that 

 the eye is compelled to dwell on the individual lines and points 

 and to grasp their true connection in all dimensions of space ; 

 it will often happen that in this process relations will be per- 

 ceived, which previous careful observation had disregarded, 

 and which may be decisive of the question under examination 

 or even open up new ones. As the microscope trains the eye 

 to scientific sight, so the careful drawing of objects makes the 

 educated eye become the watchful adviser of the investigating 

 mind ; but this advantage is lost to the observer who has his 

 drawings made by another hand. It is not one of the least of 

 von Mohl's merits, that he practised microscopic drawing under 

 the influence of the views here indicated, and sought to make 

 his figures no mere undigested copies of the objects, but an 

 expression of his own opinions about them. 



Enough has been said to show that an important portion of 

 the history of phytotomy lies between the beginning and the 

 end of the period under consideration. The distance between 

 the knowledge of the structure of vegetable tissue which existed 

 at the beginning of the century, and that of Meyen and von Mohl 

 on the same subject in 1840, is wonderfully great; in the one 

 case an uncertain groping about among obscure ideas, in the 

 other a complete exposition of the inner architecture of the 

 mature plant. But in spite of this great difference between 

 beginning and end, it is better to review the efforts of this 

 period of forty years as a connected process of historical 

 development, and, notwithstanding the interval between the ap- 

 pearance of Moldenhawer's contributions in 1812 and Meyen's 

 and von Mohl's labours about 1840, to consider the latter as 



