THE VEGETABLE AND ANIMAL KINGDOMS. 127 



reached. This may be illustrated by a simple diagram. ( 3S ) 

 The foetus of all the four classes may be supposed to advance 

 in an identical condition to the point A. 

 The fish there diverges and passes along 

 a line apart, and peculiar to itself, to its 

 mature state at F. The reptile, bird, and D 

 mammal, go on together to C, where the 

 reptile diverges in like manner, and ad- 

 vances by itself to R. The bird diverges 

 atD, and goes on to B. Here it is appa- 

 rent that the only thing required for an 

 advance from one grade to another in the 

 generative process is that, for example, the 

 fish embryo should not diverge at A, but 

 go on to C before it diverges, in which case the progeny 

 will be, not a fish, but a reptile. To protract the straightfor- 

 ward part of the gestation over a small space is all that is ne- 

 cessary. 



Xow we may never see an example of the working of the 

 actual law which is supposed to be capable of producing such 

 an advance of grade ; but something approaching to it in effect 

 has been observed. Sex is fully ascertained to be a matter 

 of development. All beings are, at one stage of the embryotic 

 progress, female ; a certain number of them are afterwards 

 advanced to be of the more powerful sex. From this it will be 

 understood that no absolute distinction exists ; all such are 

 merely apparent. The ingenious Huber first made us aware 

 of an instance, in a humble department of the animal world, 

 of arrangements being made by the animals themselves for 

 adjusting the law of development to the production of a par- 

 ticular sex. Amongst bees, as amongst several other insect 

 tribes, there is in each community but one true female, the 

 queen bee, the workers being false females or neuters ; that 

 is to say, sex is carried on in them to a point intermediate 

 between the female and male, where it is attended by sterility. 

 The preparatory states of the queen bee occupy sixteen days ; 

 those of the neuters, twenty ; and those of males, twenty-four. 

 Now it is a fact, settled by innumerable observations and ex- 



