THE INFLUENCE OF HYBRIDITY. 99 



term to two extremes. It cannot of itself produce variety of 

 origin, it is the consequence of it, and we shall see that the 

 part it takes on this matter is extremely restricted. 



White* supposes a colony composed of an equal number of 

 blacks and whites ; then he tries to find out what will happen 

 in the course of time, by supposing that a thirtieth part of 

 them die and are born each year. He arrives, by his calcula- 

 tions, at the following results : in sixty-five years the number 

 of blacks, whites, and mulattos will be equal ; in ninety-one 

 years the whites will only form one-tenth of the total popula- 

 tion, and the blacks one-tenth ; in three centuries, there would 

 not remain one hundredth part of them, either black or white. 



This proposition is true, theoretically speaking ; it is prac- 

 tically false : it rests upon what we may call an unstable equi- 

 librium. In the physical world we may, by care, happen to 

 put an ellipsoid in a state of equilibrium on the extremity of 

 its greater axis, or a cone on its apex ; these are also unstable 

 equilibria, but the least cause intervening, the smallest move- 

 ment, and the balance is instantly destroyed. If we admit 

 into White's theory a birth which does not take place, or an 

 unproductive union, the conclusions are overturned at once ; a 

 part of the new generation will preserve the primitive type,f 

 and this portion will be much more considerable than White 

 imagined. When the facts of arrest of development, quoted 

 above, are not sufficient to prove that a mongrel breed cannot 

 subsist by itself, can we anywhere find one ? Do we find a 

 people preserving for centuries a medium type between two 

 other types which gave it birth? We see them nowhere, 

 just as little as we see a race of mules. The fact is that such 

 a hybrid race, intermediate to two defined types, can only have 

 a subjective and ephemeral existence. 



The definition of the word type, both in natural history and 

 in the particular case in which we are engaged, is rather a 

 difficult matter, and which we can fed much better than we 

 can express it in writing. When we have seen a certain 

 number of men belonging to one race, the mind, without any 



* Account of the Regular Gradation of Nan, p. 146. 



f Compare W. Edwards, Des Caracteres Physiologiques, etc., p. 29. 



H2 



