102 MODES OF RESEARCH IN GENETICS 



Aside from a relatively small amount of definite 

 experimental data one's judgment is finally formed 

 on the basis of his interpretation of the vast 

 accumulation of material comprised in the recorded 

 and unrecorded experience of the breeders of 

 registered (pedigreed) livestock. 



This material recorded in the books of registra- 

 tion far exceeds in amount and in diversity any 

 which could possibly be obtained experimentally 

 on the same forms of life. It must be said, how- 

 ever, that the discussion of it with a view to an 

 analysis of the effects of inbreeding, though under- 

 taken at greater or less length by a number of 

 men including Lehndorff, von Oettingen, Bruce 

 Low, Hoesch, Chapeaurouge, Bunsow, Strang, 

 and others, has not led to results characterized 

 by the precision, the definiteness, or the quality of 

 getting at fundamentals demanded in the present 

 state of the science of genetics. 



The lack of precision and fundamental character 

 in the studies alluded to is not primarily to be 

 attributed to any inherent defect in the material. 

 In the breeding of all of the domestic animals 

 inbreeding has been practiced ; in many instances 

 to a very marked degree. Further, the manner in 

 which the inbreeding has been done (the types of 

 relationship-matings) exhibits a most intricate 

 diversity, from which different types may be 

 picked out for analysis in any reasonable quantity. 

 The records are accurate, within their limitations, 



