CHAPTER XXIV. 



THEORY AND PRACTICE IN BREEDING. 



The theoretical problems of breeding are complex 

 and need investigation, demonstration, illustration and 

 discussion. The different theories need to be given 

 their relative values in relation to practical breeding, to 

 the business of creating new values and bringing them 

 into general use. Some of the old fogy notions too of- 

 ten given undue importance, should be publicly anal- 

 yzed until they recede to their proper places with other 

 outclassed material. Statistical investigations in the 

 theory of enforced evolution promise to clear up much 

 that is now seen in a wrong or but dim light. Experi- 

 ence with large numbers of individuals of many breeds 

 of varieties, under plans for producing practical values, 

 will give many men more practical knowledge of the 

 creative work, also of the office of the multiplier of new 

 forms. Practical breeders must learn that there is ris- 

 ing a better body of thought on the underlying theory 

 of heredity and practical breeding. Students of the 

 theory on the other hand must realize what a weak 

 statement it is now possible to make of the principles 

 involved in effective breeding and by more and better 

 research improve the forms of statement for text books. 



Every student of practical breeding who has had 

 the opportunity of using large numbers of animals or 

 plants under close statistical observation realizes what 

 a complex study individuals are. In some cases of hy- 

 brids known to carry the blood lines of three or more 

 distinct races or species we are able to analyze the ani- 

 mal or plant. We can often trace each characteristic 

 to one parental stock or to another. Analysis means 

 the separation of a unit into its component parts. Syn- 

 thesis on the other hand means the placing together of 



