DR. LIVINGSTONE. 257 



Dr. Livingstone has shown that vast portions of 

 South Africa, which formerly used to be well-water- 

 ed, have been for long, and still are, undergoing a 

 rapid desiccation,* and it seems to me that that im- 

 portant fact alone is sufficient to account for many 

 of these antelopes having changed their peculiarities 

 and habits ; and with the latter, through the lapse 

 of countless ages, their size, shape, color, horns, and 

 other distinctions. Nay, farther, I entertain no 

 doubt that they are undergoing these said changes 

 at this moment, but by such a slow and gradual 

 process that it is quite imperceptible in the brief 

 space of human life, or even within the period since 

 natural history began to be studied. 



A chapter might easily be here written about 

 that singular animal, the wildebeeste, or gnu, which 

 seems to be a tolerably well-defined link between 

 the antelopes and the bovine tribe ; but I will now 

 leave the discussion of the subject to abler pens than 

 mine. 



* My own personal observation in South Africa abundantly 

 confirms that remark of the doctor's. 



B 



