THEORIES AND CONCLUSIONS 
but the result of myriad complex chemical 
affinities of later date? 
“Past tendencies must fade somewhat 
as the new ones are added, and as each 
individual has ancestors in untold numbers, 
and as each is bound to the other like the 
numerous threads of a fabric, individuals 
within a species, by thus having very numer- 
ous similar lines of heredity, are very much 
alike; yet no two are just alike. Cross two 
species and see what the results will be: 
Sharp mutations and variations appear, not 
in the first generation, as the two are bound 
together in a mutual compact, which, when 
unloosed by the next and succeeding gen- 
erations, will branch in every direction as 
the myriad different lines of heredity combine 
and press forward in various new directions. 
A study of plants or animals belonging to 
widely different species and even genera 
which have been under similar environment 
for a long time will always show a similarity 
in many respects in the various means they 
are compelled to adopt for defense in the 
preservation and reproduction of life. Desert 
plants often have thorns, acrid qualities and 
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