The Laws of Heredity. 155 



(about which there can be no doubt), but whether there are cases 

 where it derives them in equal degree from both. If such a case 

 were to occur, we could not show that it did, especially as regards 

 moral resemblances. To that end we must needs have exact pro- 

 cesses of measurement, which do not exist; we should have to 

 estimate quantities and not qualities. The foregoing examples, 

 and all the others we might accumulate, could prove only this one 

 thing, that there is always a more or less marked preponderance 

 of one of the two parents. Cases occur where the preponderant 

 action of the father or of the mother is manifested in a singular 

 way, each parent seeming to have, as it were, chosen some par- 

 ticular organ. Thus the father may transmit to the child the brain, 

 and the mother the stomach ; one the heart, the other the liver ; 

 one the great intestine, the other the pancreas ; one the kidneys, 

 the other the bladder. These facts have been established by 

 animal and human anatomy. They give the organic reason for the 

 intercrossing of instincts, which is often so curious, and of the 

 morbid and passionate predispositions of both parents in the 

 child. 



Sometimes, too, one of the parents transmits the entire physical, 

 the other the entire moral nature. The most curious and incon- 

 testable instance of this is the case of Lislet-Geoffroy, engineer 

 in Mauritius. He was the son of a white man and of a very 

 stupid negress. In physical constitution he was as much a negro 

 as his mother; he had the features, the complexion, the woolly 

 hair, and the peculiar odour of his race. In moral constitution he 

 was so thoroughly a white as regards intellectual development, that 

 he succeeded in vanquishing the prejudices of blood, so strong 

 in the colonies, and in being admitted into the most aristocratic 

 houses. At the time of his death he was Corresponding Member 

 of the Academy of Sciences. 



Thus we are brought to the examination of cases of unilateral 

 heredity the word unilateral being here taken, as has been ex- 

 plained, in a restricted sense. 



