CHAP, ii.] Phytotomy in the Eighteenth Century. 255 



adjoining cells have left on the wall of the spiral vessel, but 

 explains it as wrinkles caused by desiccation. 



Hedwig was without doubt a very practised microscopist, and 

 he constantly recommended the extremest care in the interpre- 

 tation of all that the instrument reveals ; but if an observer so 

 careful and practised, who moreover was provided with a glass 

 of tolerably strong magnifying power, fell into such gross mis- 

 takes, it cannot surprise us if others, as P. Schrank, Medicus, 

 Brunn, .and Senebier, accomplished still less. These highly 

 unimportant achievements are all that mark the close of the 

 i 8th century. 



