HISTORY OF ZOOLOGY 



37 



a period of twenty years which commanded the attention of scien- 

 tists as well as of the public generally. In 1858 he read a joint paper 

 with Alfred Russel Wallace, a contemporary who had reached the 

 same conclusion, on the theory of natural selection. That same year 

 Darwin published his book Origin of Species which is a classic in 

 its field and familiar to all scholars. 



Gregor Mendel (1822-1884) was an Austrian monk who carried 

 on experiments with the breeding of garden peas in the cloister 

 garden. From his work there, he derived the original laws of 

 heredity. His results were first published in an obscure Swiss paper 



Fig. 9. — Louis Pasteur (1822-1895) contributed much to the knowledge of bacteria 

 and disease. (From Garrison, History of Medicine, W. B. Saunders Company.) 



in 1866 and were not really discovered and appreciated until 1900. 

 He was the founder of genetics. He crossed different kinds of peas 

 and found that the offspring in the first generation all resembled 

 one parent. When these offspring were interbred he found that 

 three-fourths of their progeny resembled one grandparent, and the 

 remainder resembled the other. From these facts he referred to 

 characteristics of the former group as dominant and those of the 

 latter as recessive. The facts which he established are now known 

 as Mendel's Laws of Heredity. 



Louis Pasteiir (1822-1895) was a French scientist who had been 

 trained in chemistry but became one of the outstanding pioneers 



