70 TILLEES OF THE GKOUND CHAP. 



This is an example of the kind of work which 

 is done, and can be done profitably, by experts such 

 as those of the Bureau of Plant Industry ; and it 

 shows how much they can help the farmers. For 

 remember that the more alfalfa each particular 

 field can be made to grow, the more beasts the 

 farmer can rear and keep. The more beasts he 

 has, the more manure he gets for his land, and the 

 more labour to plough his land. The alfalfa is the 

 base on which stands the whole pyramid of his 

 prosperity. 



Let us take one other example of the work of 

 the Bureau, the very interesting one of the prickly 

 pear, which is really a kind of cactus. Most people 

 have an idea that cactuses grow in all deserts, but 

 in point of fact they belong to the American 

 deserts. When the Spaniards first went to Mexico 

 they found there the different kinds of prickly 

 pears, or opuntias, to give them their scientific 

 name. As the pictures on pages 73 and 74 show, 

 prickly pears are made up of a great number of flat 

 green plates shaped like racquets and covered with 

 prickly spines. Like other cactuses, they flower 

 freely, but they differ from most in producing nice 

 sugary fruits, a little like green figs in appearance. 

 In ancient Mexico these fruits were eaten, and 

 the plants were cultivated for the sake of the 

 fruits. The plants have another interest, for on 



