RELATIVE INFLtTENCB OF THE PARENTS. 75 



framework, or bones and muscles, more particularly 

 those of the limbs, the organs of sense and skin ; while 

 the female parent chiefly determines the internal struct- 

 ures and the general quality, mainly furnishing the vital 

 organs, i. e., the heart, lungs, glands and digestive 

 organs, and giving tone and character to the vital func- 

 tions of secretion, nutrition and growth. "Not how- 

 ever that the male is without influence on the internal 

 organs and vital functions, or the female without influ- 

 ence on the external organs and locomotive powers of 

 their oflFspring. The law holds only within certain re- 

 strictions, and these form as it were a secondary law, 

 one of limitations, and scarcely less important to be 

 understood than the fundamental law itself." 



Mr. Orton relies chiefly on the evidence presented by 

 hybridis, the progeny of distinct species, or by crosses 

 between the most distinct varieties embraced within a 

 single species, to establish his law. The examples 

 adduced are chiefly from the former. The mule is the 

 progeny of the male ass and the mare ; the hinny, that 

 of the horse and the she ass. Both hybrids are the 

 produce of the same set of animals. They dififer widely, 

 however, in their respective characters — the mule in 

 all that relates to its external characters having the 

 distinctive features of the ass, — the hinny, in the same 

 respects having all the distinctive features of the horse ; 



