XVII. HEREDITY, VARIATION, PLANT AND AMMAL 



BREEDING 



Problems. — To determine what makes the off sj, vine! of ani- 

 JYials or plants tend to he like their f)arents. 



To determine what makes the nffsjn^ii}^ of animals and 

 plants differ from their parents. 



To learn about some methods of plant and animal breeding. 



(a) By selection. 



(b) By hybridizing. 

 (e) By other methods. 



To learn about some methods of improving the human race. 



(a) By eugenics. 



(b) By euthenics. 



Suggestions for Laboratory Work 



Laboratory exercise. — On variation and heredity among members of 

 a class in the schoolroom. 



Laboratory exercise. — On construction of curve of variation in meas- 

 urements from given plants or animals. 



Laboratory demonstration. — Stained egg cells (ascaris) to show cliro- 

 mosomes. 



Laboratory demonstrations. — To illustrate the purt phiyed in phiiit or 

 animal breeding by 



(a) selection. 



(6) hybridizing. 



(c) budding and grafting. 



Laboratory demonstration. — From charts to illustrate how human 

 characteristics may be inherited. 



To THE Tkaciier. — T\w cont.onts of this oh:ii)t(M- will i>r()l)al»l\- prove of morr 

 interest and, if seriously taken up l)\- (eaclier and pui)ils, of more lasting value than 

 any other part of the eovu'se. 'V\\v immense siKnili<'anee of variation and heredity 

 and the application of these factors in euKenics eertaii»ly make a theme of vital 

 interest. The direct teaching of sex hygiene in the public sccomlary school is not 

 recommended, both because of lack of preparation (ui the part of teachers. l>ecauso 

 of the intimacy of contact rcciuired lietween teacher and pupil, making work with 



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