CELLS AND THE ORGANISM = 45 
to make up the Cladophora plant. It may 
easily be shown that the co-ordination is 
a real one, and that it depends in some way 
on the mutual reactions between one cell and 
another, by means of an experiment on one 
of the marine species of the genus. If the 
Fig. 6.—Cladophora sp. 1.—General habit. IJ.—Magnified 
lament. 
plant be placed in sea-water to which a 
strong salt solution is slowly added (up to 
about 12°5 %), the protoplasm of each of 
the cells contracts away from the walls, and 
forms an ellipsoidal mass within each cell 
cavity. The protoplasts then surround them- 
selves with new walls. After allowing them to 
