LUTHER BURBANK 
We may take it as a safe observation that the 
simpler the form of life, the less the tendency 
toward variation; the more complex, the greater 
the opportunity for individual differences. 
So, in the simpler subkingdoms, and in the 
more general divisions down to and including the 
order, the lines of division are more readily 
differentiated, and the work of classification has 
been fairly free from quarrels. 
But as the order breaks up into families, and 
the family breaks up into genera, and the genus 
breaks up into species, and the species breaks up 
into varieties, and variations tend more and more 
to carry the individual away from its kind, there 
are to be found dissentions and differences of 
opinion which could hardly be chronicled in 
twelve full volumes of this size. 
Nor is this divergent opinion surprising. 
It is said that, of an iceberg floating in the sea, 
but one-eighth is visible to the surface observer, 
while seven-eighths of the mass are submerged 
beneath the water line. 
Who, from looking at the one-eighth in view, 
could be expected to draw an accurate detail 
picture of the iceberg as a whole? 
The vegetable kingdom which presents itself 
to our vision today has been under observation, 
[220] 
