HEREDITY 547 



evidence, and which shows the degree to which the various gen- 

 erations have contributed to the results. 



Continued selection will shift the type in any desired direction, 

 and after a few generations it will " breed true " in its new form. 

 As variability is not greatly reduced by selection, there is always 

 opportunity for improvement so far as variability is concerned. 



SPECIAL EXERCISES 



1 . Exercises in great variety in forming regression tables and in deducing 

 the conclusions. 



2. Investigations into the operations of Mendel's law, by the examina- 

 tion and identification of laboratory material and if possible by the actual 

 raising of crossed forms for the purpose. 



3. Special and definite applications of the law of ancestral heredity 

 to the problems of the breeder, especially in crossing, grading, and line 

 breeding. 



ADDITIONAL REFERENCES 



ALTERNATIVE INHERITANCE. By Karl Pearson. Proceedings of the 



Royal Society, LXXII, 505-510. 

 AMERICAN TROTTING RECORDS AS DATA FOR HEREDITY STUDIES. 



By Francis Galton. Proceedings of the Royal Society, LXII, 



310-315. 

 BATESON ON PEARSON'S CONCEPTION OF HEREDITY. Proceedings of 



the Royal Society, LXIX, 193-205 ; Pearson's answer, LXIX, 450. 

 CHANCES OF DEATH. By Karl Pearson. Science, VI, 328-330. 

 CONTRIBUTION OF SEVERAL ANCESTORS TO OFFSPRING. By Francis 



Galton. Proceedings of the Royal Society, LXI, 401-413. 

 CORRELATION BETWEEN LONGEVITY AND FERTILITY. By Karl Pear- 

 son. Proceedings of the Royal Society, LXVII, 159-179* 333-337- 

 CRITERION TO TEST THEORIES OF HEREDITY. By Karl Pearson (1904). 



Proceedings of the Royal Society, LXXII I, 262-280. 

 Do VARIETIES RUN OUT? By J.Craig. Gardening, 1899, pp. 278-279 $ 



also in Experiment Station Record, XI, 152. 

 EXPERIMENTAL EVIDENCE UPON MENDEL'S LAW. By L. H. Lock. 



Nature, LXX, 601-602; by Karl Pearson, 626-627. 

 EXPERIMENTAL STUDIES IN HEREDITY. Corn Report of the Royal 



Society, 1902, p. 160 ; also in Experiment Station Record, XVII, 634. 

 EXPERIMENTAL ZOOLOGY. By T. H. Morgan. Chapters VI and VII, 



pp. 66-166. 

 EXPERIMENTS IN CROSSING WHITE AND BLACK OATS. By J. H. Wilson. 



Nature, 1904, p. 413 ; Experiment Station Record, XVI, 462. 



