CELLS AND THE ORGANISM § 47 
instances connecting strands of protoplasm 
have been demonstrated, and these serve as 
the obvious channels of direct communication 
between the living contents of adjacent cells. 
When the interchange has been sufficiently 
interrupted the old order cannot be again 
restored. The cells are released, as it were, 
from the influence that previously controlled 
them and caused them to be welded together 
into a higher individuality. Each cell, thus 
breaking away from the union, reverts to 
a more primitive condition, recovering an 
independence akin to, and perhaps identical 
with, that which distinguishes zoospores 
and other reproductive cells that are set 
free from the organism which gives them 
birth. 
Although the simpler filamentous alge, 
and especially the branching kinds, share with 
the primitive flattened leaf-like types the 
advantage of disposing their surfaces so as 
to make the most of the means of illumin- 
ation, they yet remain far behind the more 
advanced types, in which other functions 
beside those of photosynthesis press for 
notice. 
The larger seaweeds, although their green 
colour is masked by yellow or red pigment, 
are as dependent on light for the manu- 
facture of their food as are their simpler 
green companions. But their s?ze introduces 
an element of physiological complexity. 
lt will be remembered that it is only the 
