THE FLOCKS AND HERDS 149 



captives, the condition of these animals will afford a fair field 

 for the reformer's care. 



The geologist who is acquainted with the mammalian life 

 of the Middle Tertiary period readily notes the fact that the 

 variety in genera and species appears to be much greater 

 than it is at the present time. A great number of forms, 

 differing somewhat widely from those now in existence, then 

 abounded in the Americas and the Old World. It may 

 at first sight seem unfortunate that man did not have the 

 chance to essay his domesticative arts on that older and 

 apparently richer life. A closer examination, however, leads 

 us to see that the species of that time, though more numerous 

 than those of the present, were on the whole less fitted for 

 our use than the fewer but more completely differentiated 

 kinds with which we have had to deal. The multitude of 

 kinds which we find in the Mesozoic period indicates that the 

 life was in a state more experimental than that to which it has 

 attained. A host of forms on their way towards the speciali- 

 zation which has now been attained have been removed from 

 the sphere, in the manner of a scaffolding from a completed 

 structure. That which has been left remains because it has 

 successfully accomplished the task of reconciliation with envi- 

 ronment, or, in simpler phrase, because it has learned to do 

 things which were useful and profitable in a more perfect 

 manner. 



As an illustration of the fact that the animals of to-day 

 are better fitted to be the help-meets of man than were their 

 ancestors of an earlier time, we may note the state of the 

 horse at the time when that genus was undergoing its devel- 

 opment in the region about the upper waters of the Missouri. 

 As may be imagined, the long and difficult passage from the 



