446 CLASS MAMMALIA. 



second species be found assimilated to a third group, on 

 the other, so that in fact all organization, including both 

 the animal and vegetable kingdom, be irregularly reticu- 

 lated together, we seem naturally led to the inquiry whe- 

 ther these assimilated individuals have ever reproduced a 

 third race differing from both, and the zoological cata- 

 logue has been thus enlarged, and to what extent. 



Although we by no means intend to enter into the dis- 

 cussion of a subject of this nature, but merely to allude to 

 it en passant, it may be proper not to quit it precipitately 

 without adverting to the ordinary-admitted conditions of 

 hybrid animals. 



Sterility seems one of the most determined of these con- 

 ditions. It appears to be the mean employed by nature to 

 prevent the very effects to which we have just ventured to 

 allude, and if universal in its application, must at once put 

 an end to the possibility of factitious races springing from 

 these unnatural intercourses. 



It is from the domesticated or tamed races that we prin- 

 cipally draw our facts upon this subject. Those specifi- 

 cally different, as the Horse and Ass, being the most fami- 

 liar to us, produce the ordinary Mule, which is steril in 

 effect, though it may occasionally produce offspring ; for 

 even then such offspring is found to degenerate from its 

 parent, and to be perfectly incapable of reproduction. But 

 the events of the sequestered forest and trackless wilder- 

 ness are less easy of detection. In relation to these, we 

 must be content with few facts and many analogies. 



The course of reproduction of the larger Felinse has, of 

 late years, been frequently open to observation in the me- 

 nageries, and one cannot but feel some surprise that the 

 breeding these animals in a state of confinement should be 

 comparatively matter of modern experiment only. We 

 have now not only instances of these animals breeding in 

 the ordinary manner, but we have instances of varieties so 



