112 HYPOTHESIS OF THE DEVELOPMENT Of 



change upon the embryo. It is not the different food 

 which effects a metamorphosis. All that is done is mere- 

 ly to accelerate the period of the insect's perfection. By 

 the arrangements made and the food given, the embryo 

 becomes sooner fit for being ushered forth in its image or 

 perfect state. Development may be said to be thus ar- 

 rested at a particular stage — that early one at which the 

 female sex is complete. In the other circumstances, it is 

 allowed to go on four days longer, and a stage is then 

 reached between the two sexes, which in this species is 

 designed to be the perfect condition of a large portion of 

 the community. Four days more make it a perfect male. 

 It is at the same time to be observed that there is, from 

 the period of oviposition, a destined distinction between 

 the sexes of the young bees. The queen lays the whole 

 of the eggs which are designed to become workers, before 

 she begins to lay those which become males. But proba- 

 oly the condition of her reproductive system governs the 

 matter of sex, for it is remarked that when her impregna- 

 tion is delayed beyond the twenty-eighth day of her entire 

 existence, she lays only eggs which become males. 



We have here, it will he admitted, a most remarkable 

 illustration of the principle of development, although in 

 an operation limited to the production of sex only. Let 

 it not be said that the phenomena concerned in the gene- 

 ration of bees may be very different from those concerned 

 in the reproduction of the higher animals. There is a 

 unity throughout nature which makes the one case an in- 

 structive reflection of the other. 



We shall now see an instance of development operat- 

 ing within the production of what approaches to the cha- 

 racter of variety of species. It is fully established that a 

 human family, tribe, or nation, is liable in the course of 

 generations, to be either advanced from a mean form to a 

 higher one, ox degraded from a higher to a lower, by the 

 influence of the physical conditions in which it lives. 

 The coarse features, and other structural peculiarities ot 

 the negro race, only continue while these people liva 

 amidst the circumstances usually associated with barbar- 

 ism In a more temperate clime, and higher social state* 

 the face and figure become greatly refined. The few 

 African nations which possess any civilization also exhi- 

 bit forms approaching the European ; and when the same 

 people in the United States of America have enjoyed a 



