THE CARDOON. 153 



occurs in these latitudes on both sides of the Cor- 

 dillera, across the continent. I saw it in unfre- 

 quented spots in Chile, Entre Rios, and Banda 

 Oriental. In the latter countiy alone, very many 

 (probably several hundred) square miles are covered 

 by one mass of these prickly plants, and are im- 

 penetrable by man or beast. Over the undulating 

 plains, where these great beds occur, nothing else 

 can now live. Before their introduction, however, 

 the surface must have supported, as in other parts, 

 a rank herbage. I doubt whether any case is on 

 record of an invasion on so gi'and a scale of one 

 plant over the aborigines. As I have already said, 

 I nowhere saw the cai'doon south of the Salado ; 

 but it is probable that in pro])ortion as that coun- 

 try becomes inhabited, the cardoon will extend its 

 limits. The case is different with the giant thistle 

 (with variegated leaves) of the Pampas, for I met 

 with it in the valley of the Sauce. According to 

 the principles so well laid down by Mr. Lyell, 

 few countries have undergone more remarkable 

 changes since the year 1535, when the first colo- 

 nist of La Plata landed with seventy-two horses. 

 The countless herds of horses, cattle, and sheep, 

 not only have altered the whole aspect of the vege- 

 tation, but they have almost banished the guanaco, 

 deer, and ostrich. Numberless other changes must 

 likewise have taken place; the wild pig in some 

 parts probably replaces the peccari ; packs of wild 

 dogs may be heard howling on the wooded banks 

 of the less frequented streams ; and the common 

 cat, altered into a large and fierce animal, inhabits 

 rocky hills. As M. d'Orbigny has remarked, the 

 increase in numbers of the can-ion-vulture, since the 

 introduction of tlie domestic animals, must have 

 been infinitely gi'eat ; and we have given reasons 

 for believing that thev have extended their south- 



