THE CEU, AND ITS LIFE. 



23 



nowadays when speaking of the chamber of a prison as a 

 cell. Although Hooke's notion regarding these chambers 

 or cells has long since been changed, the term he applied 

 to them has remained, and there is little probability that it 

 will ever be displaced, so firmly is it established in biolog- 

 ical science. 



Fig. 1. A SECTION OF WOOD SHOWING 

 THE CHAMBERED APPEARANCE. 



Fig. 2. CELLS IN GROWING WOOD. 



Several years later (in 1671) Malpighi and Grew each 

 published a treatise on structural botany in which this 

 chambered or cellular appearance was noted as occurring 

 in many other vegetable tissues besides cork. For more 

 than a century nothing further was done, and it was not till 

 the beginning of our own century that the observations in 

 this direction were renewed. In 1812 Moldenhauer, a Dutch 

 scientist, by macerating plant tissues succeeded in isolating 

 individual cells. (Experiment easily repeated with a ripe, 

 mealy apple.) This changed the idea of Hooke that cells 

 were but empty chambers in a homogeneous mass, to the 

 correct view that cells are individual structures having a 

 solid wall enclosing the chamber. In this way the cell 

 wall and not the empty space seemed to be the essential 

 thing. Soon after this, however, Corti and Amici found 

 that many cells are filled with a liquid sap, and in several 

 instances they had observed this sap circulating in the cell 

 without being affected by an external power. Such further 

 observations emboldened Meyen, in 1838, to venture the 

 assertion that a part of the cell sap must surely be alive. 



