CHAPTER X 



EXPERIMENTAL STUDY OF INHERITANCE 



As regards Mendel's Law, " The experiments which led to this advance 

 in knowledge are worthy to rank with those that laid the foundation 

 of the atomic laws of chemistry." — Bateson. 



" The breeding-pen is to us what the test-tube is to the chemist — an 

 instrument whereby we examine the nature of our organisms and deter- 

 mine empirically their genetic properties." — Bateson. 



" That Hurst can predict the difference between the result of mating 

 two pairs of rabbits externally identical, by means of a knowledge of 

 the difference between their gametic constitutions acquired by previous 

 breeding from them, constitutes, it seems to us, the longest stride the 

 study of heredity has made for some time past." — Nature, Ixxi. 1905, p. 315. 



§ I. Mendel's Discoveries. 



§ 2. Theoretical Interpretation. 



§ 3. Elaborations. 



§ 4. Illustrations of Mendelian Inheritance. 



§ 5. Mendel's Discovery in Relation to Other Conclusions. 



§ 6. Practical Importance of Mendel's Discovery. 



§ 7. Other Experiments on Heredity. 



§ 8. Consanguinity. 



§ I. Mendel's Discoveries 



In 1866 Gregor Johann Mendel,* Abbot of Briinn, published 

 what some regard as one of the greatest of biological discoveries. 

 After many years of patient experimenting, chiefly with the 



* Gregor Johann Mendel was born in 1822, the son of well-to-do peasants 

 in Austrian Silesia. He became a priest in 1847, and studied physics 



