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ample, then we feel reasonably safe in thinking we are on the 
right track. The remaining ten may be errors of observation, or 
errors of fact in some other way. When possible, they are in- 
vestigated and their cause or causes ascertained. 
But facts themselves, however accurate, have only a nominal 
value, unless they are gathered for a purpose or centered around 
an idea. The world teems with ungrouped facts. And scien. 
tists are busy discovering new ones and assorting those already; 
known into orderly collections with some meaning. 
Through peas in the hands of a scientifically trained priest 
and teacher, the world came into possession of another core or 
idea center for fact grouping. The facts regarding heredity 
known then and since have helped to give birth to the science 
of genetics. 
In previous paragraphs, I said eye-color in people is inherited 
through the operation of the same laws as eye-color in peas. 
If Mendel had tried to discover these laws by studying people, 
he probably would have failed. He understood very clearly the 
smportance of having the best material to work with and spent 
much time in trying to find it. That is why he chose peas. 
But how is eye-color in human beings inherited? People com- 
monly describe many kinds of eye-color in themselves—hazel, 
gray, blue, black, brown, etc. Reduced to the simplest terms, 
eyes either have brown pigment or they are without it. “ Blue 
eyes,” as the term is commonly used in science, means the ab- 
sence of all brown pigment. Even a small speck or two of 
brown pigment in the eye classifies the person as brown-eyed in 
genetics. 
Blue-eyed people marry. Except in rare instances, their chil- 
dren are all blue-eyed. A blue-eyed individual desiring brown- 
eyed children must marry a brown-eyed individual. Eyes as yet 
have not been brought under the art of dyeing. 
Nith brown-eyed people the case is somewhat different, be- 
cause, genetically, two kinds of brown-eyed people walk the 
earth, those pure for brown-eye and those hybrid for brown- 
eye. Brown-eyed people with both chromosome seats occupied 
by brown-eye determiners will have only brown-eyed children. 
But brown-eyed people with a brown-eye determiner in one 
