220 Introduction. [BOOK n. 



stem, while the soft, pulpy, succulent condition of the unripe 

 seeds and seed-vessels seemed to point to their identity with 

 the pith. That not only are juices contained in plants, but 

 that they must move in them, could not escape the simplest 

 reflection ; and further, the bleeding of the vine, the flow of 

 gum from resiniferous trees, the gushing of a milky juice from 

 the wounds of certain plants, exhibited so striking a resem- 

 blance to the bleeding of a wound in the body of an animal, 

 that the idea of canals inside the plant, which, like the veins in 

 animals, contain those juices and set them in motion, ap- 

 peared quite natural, as we see plainly from Cesalpino's reflec- 

 tions on these structural conditions. If we add that it was 

 known that the seeds are enclosed in the fruits, and that the 

 embryo, together with a pulpy mass (cotyledons and endo- 

 sperm), are in their turn enclosed in the seed, we have pretty 

 well the whole inventory of phytotomic knowledge up to about 

 the middle of the seventeenth century. 



With careful preparation and skilful dissection of suitable 

 parts of plants, and attentive consideration of the changes pro- 

 duced by decay and corruption, anatomical knowledge might 

 have been considerably enlarged at an earlier time ; but seeing 

 is an art that must be learnt and cultivated; a definite aim 

 and end must stimulate the observer into willingness to see 

 exactly, and to distinguish and connect together correctly what 

 he sees. But this art of seeing was not far advanced in 

 the middle of the iyth century. All that was achieved in 

 this direction did not go beyond the distinguishing the outer 

 organs of leaf-forms and stem-forms, and we have seen in the 

 first book how unsuccessful was the attempt to distinguish the 

 minuter parts of the flower and fruit. 



The invention of the microscope made small things seem 

 large, and revealed to sight what was too small to be seen 

 without it ; but the use of magnifying glasses brought an ad- 

 vantage with it of a different kind it taught those who used 

 them to see scientifically and exactly. In arming the eye with 



