THE PHENOMENA OF ORGANIC NATURE. 141 



would be just what we find them to be. In other 

 words, the hypothetical cause is, so far, competent to 

 produce effects similar to those of the real cause. 



Take, again, another set of very remarkable facts, — 

 the existence of what are called rudimentary organs, 

 organs for which we can find no obvious use, in the 

 particular animal economy in which they are found, 

 and yet which are there. 



Such are the splint-like bones in the leg of the 

 horse, which I here show you, and which correspond 

 with bones which belong to certain toes and fingers 

 in the human hand and foot. In the horse you see 

 they are quite rndimentary, and bear neither toes nor 

 fingers; so that the horse has only one "finger" in 

 his fore-foot and one " toe" in his hind-foot. But 

 it is a very curious thing that the animals closely 

 allied to the horse show more toes than he; as the 

 rhinoceros, for instance : he has these extra toes well 

 formed, and anatomical facts show very clearly that he 

 is very closely related to the horse indeed. So we 

 may say that animals, in an anatomical sense nearly 

 related to the horse, have those parts which are rudi- 

 mentary in him, fully developed. 



Again, the sheep and the cow have no cutting-teeth, 

 but only a hard pad in the upper jaw. That is 

 the common characteristic of ruminants in general. 

 But the calf has in its upper jaw some rudiments of 

 teeth which never are developed, and never play the 

 part of teeth at all. "Well, if you go back in time, you 

 find some of the older, now extinct, allies of the rumi- 

 nants have well-developed teeth in their upper jaws ; 

 and at the present day the pig (which is in structure 



