COMPOUND ORGANISMS 201 
chemical reactions that have gone on and 
are still going on within it. These reactions 
are nicely adjusted, and are readily interfered 
with or encouraged by the conditions under 
which they take place. The result is per- 
ceived in a delicate adjustment of growth 
(Wy 
Wp Wy )) al 
\ Q 
- 
Fig. 234.—Peltigera canina, a lichen. F, the fructification. 
whereby the different parts are so correlated 
to each other that excessive development 
of one part carries with it its own order of 
arrest, whilst deflection of nutrition to or 
from any part will, of course, correspondingly 
affect growth in that region. 
But, nevertheless, the parts of which the 
