40 THE BOOK OF NATURE STUDY 



different mammals as possible, for in the hands of an enthusiastic 

 teacher these dry bones may indeed be made to live. The 

 different forms of teeth, and their relation to the food and habits 

 of the creatures to which they belong, are matters of the highest 

 interest and importance. Skulls of small animals, both of birds 

 and mammals, can be readily made by maceration in cold water, 

 or more quickly by slow boiling, or rather simmering, in water 

 to which a trace of soda has been added. Of course great care 

 must be taken to preserve all teeth or loose bones which may 

 become detached in the process. But this by the way. Our 

 conversation is of pigs, the only animals which are credited with 

 the power of seeing the wind ! 



The pig is a member of the order Ungulata or hoofed animals. 

 And it belongs, like the oxen, sheep and deer, to the " even-toed " 

 group of that order. That is to say, it has a " cloven " hoof. 

 The horse, on the other hand, with the pig-like tapir, and the 

 rhinoceros, for example, belongs to the " odd-toed " solid-hoofed 

 group of this order, wherein the third toe is always larger than 

 the rest, and symmetrical in itself. Where four toes are present, 

 as in the fore-foot of the tapir, the outer toe, which always answers 

 to the fifth toe, is always small. In the horse, as we have already 

 pointed out, this reduction in the number of the toes has gone still 

 further, only the third being left. In itself the number of the toes 

 is no very important matter, but it becomes important when 

 the reasons for this reduction are taken into account. Thus, the 

 ancestors of these animals were short-legged, and lived in swamps 

 and marshy ground. As they gradually moved to drier land, 

 affording less cover, greater speed, as in the case of the horse, 

 became necessary. And hence the legs became longer, and more 

 work was thrown on the larger third toe. The other toes, becoming 

 less and less useful, gradually diminished, and finally disappeared. 



All the various races or breeds of domesticated pigs are 

 descended either from the wild boar of Europe or the wild pig of 

 India. 



The commonest types of these domesticated races are white in 

 colour, and but scantily clothed with hair ; but in cold climates 

 a thick coat is developed, and this is supplemented by a well- 

 developed under-fur. 



