MENDEL'S EXPLANATION 167 



Table to illustrate Mendel's explanation of 

 Segregation in the 1:2:1 Ratio. 



It will at once be seen that the proportions in 

 which the three kinds of plant — pure tall, hybrid 

 tall and pure dwarf — would be expected to occur on 

 the basis of this theory is exactly that in which they 

 do occur. 



The fact that the theory is in perfect accord with 

 the facts which it attempts to explain is not, of 

 course, proof that the theory is true ; no one would 

 invent a theory which did not fit the facts. This 

 is, however, not the place to discuss the question 

 how nearly true it is, for we are concerned now with 

 Mendel's theory as stated by him, and not with the 

 question whether it is true or not, which will be 

 dealt with in a later chapter. 



It was stated, categorically, above that the four 

 kinds of unions of germ cells occurred with equal 

 frequency. The truth of this statement can be 

 tested in the following way : Two people each take 

 a coin, and they both toss it at the same time. This 

 act is repeated, say, a thousand times, and the result 



