130 PLANT GROWTH 



are slight. If you made the cross a great many times, how- 

 ever, the average ratio would be close to 3 : 1. The reasons 

 for the deviations are based on the laws of chance which we 

 need not go into here. But anyone who has played bridge 

 knows that the laws of chance are capricious to say the least. 

 That is why precise ratios are not to be expected, but may 

 occur even in a small number of plants by chance alone. 



But, let us consider Mendel's work once more. It was a 

 model in experimental research, and its importance as a mile- 

 stone in the history of biology, science, and human philoso- 

 phy can not be overemphasized. Without knowledge of 

 chromosomes or genes Mendel worked out the basis for the 

 inheritance of characters. The laws which he formulated 

 have since been shown to hold for every organism, plant or 

 animal, which reproduces sexually. It is surprising, then, 

 that a paper of such fundamental importance to the entire 

 scientific world as well as to the layman should have gone 

 unnoticed at the time of its publication. The paper was read 

 before the Natural Science Society of Briinn (Brno) in 1865 

 and published in the Transactions of that society in 1866. 

 It received little comment and was filed away on the shelves 

 to be forgotten. Mendel, realizing the importance of his dis- 

 coveries, wrote to the outstanding European naturalist of 

 the time, Carl Naegli, but the significance escaped even this 

 scientist. Mendel died still believing in his work and its 

 importance. It wasn't until a generation later, in 1900, that 

 his paper was discovered again. Three men, DeVries of 

 Holland, Correns of Germany, and Tschermak of Austria, 

 each one independently of the others, discovered Mendel's 

 paper, in the library at Brunn, stuffed back on a shelf where 

 it had accumulated dust for 30 years. Each of the three 

 scientists reported the finding of the paper and, although 

 each had gotten similar results in his own work, they very 

 properly gave Mendel the credit for his complete under- 

 standing of the whole problem. 



