VESSEI.b. lo 



oi'the ceils is somewhat diveysified, varying in conse 

 quence of the pressure of the juices with which they 

 are filled, as well as of the more substantial organs by 

 which they are surrounded ; usually, however, they 

 are hexagonal, and the student who has no other means 

 of gaining an adequate idea of their form and arrange 

 ment may profit by the illustration of Grew, who hap- 

 pily compared them to the bubbles that float on the 

 surface of fermenting liquors. 



