248 Phytotomy in the Eighteenth Century. [BOOK n. 



but without a mirror, an instrument which must have served 

 therefore for observing with the light from above on an 

 opaque surface ; the objective was a simple lens. But to 

 magnify objects more strongly, he says that he used a simple 

 instead of this compound instrument, as was more the custom 

 at the time. Like a true amateur Wolff submitted all sorts of 

 small and delicate objects to his glass, without examining any 

 of them thoroughly and persistently. His phytotomic gains 

 were small ; he observed for instance that starch-flour (powder) 

 consists of grains, but believed from the way in which they 

 refracted light that they were small vesicles filled with a fluid ; 

 yet he satisfied himself that these grains are already in the 

 grains of rye and therefore not produced in the grinding. He 

 laid thin sections of portions of plants on glass which was too 

 imperfectly polished to allow of his seeing anything distinctly. 

 His pupil Thiimmig in his 'Meletemata' (1736) addressed 

 himself to the subject with still less skill. By the case of 

 these two men we may see plainly that want of success was 

 due much less to the imperfectness of the microscope than to 

 unskilful management and unsuitable preparation. But Wolff 

 and Thiimmig at least endeavoured to see something for 

 themselves of the structure of plants ; a famous botanist of 

 the time, Ludwig, plainly never made a similar attempt, for 

 in his ' Institutiones regni vegetabilis' (1742) he speaks of the 

 inner structure of the plant in the following manner ; ' Laminae 

 or membranous pellicles, so connected together that they form 

 little cavities or small cells and often reticulated by the inter- 

 vention of fine threads, form the cell-tissue which we see 

 pervading all parts of plants. These are what Malpighi and 

 others call tubes, since they appear in different parts in the 

 form of rows of connected vesicles ! ' Boehmer's ' Dissertatio 

 de cellulose contextu ' (1785) is still worse; 'White elastic 

 thicker or thinner fibres and threads woven together of 

 differing shape and size form cavities or cells or caverns, 

 and are usually known by the name of cell-tissue.' We see 



