CHAP. XVIII.] SHRIKE AND KINGFISHER. 247 



abundant than the acorns, we have still to explain what prin 

 ciple in vegetable life favors the rotation. Liebig adopts De 

 Candolle s theory, as most probable. He supposes that the roots 

 of plants imbibe soluble matter of every kind from the soil, and 

 absorb many substances not adapted for their nutrition, which 

 are subsequently expelled by the roots, and returned to the soil 

 as excrements. Now, as excrements cannot be assimilated by 

 the plant which ejected them, the more of these matters the soil 

 contains, the less fertile must it become for plants of the same 

 species. These exudations, however, may be capable of assimi 

 lation by another perfectly different kind or family of plants, 

 which would flourish while taking them up from the soil, and 

 render the soil, in time, again fertile for the first plants. &quot; Dur 

 ing a fallow,&quot; says Liebig, &quot; the action of the sun and atmos 

 phere, especially if not intercepted by the growth of weeds, 

 causes the decomposition of the excrementitious matters, and 

 converts the soil into humus or vegetable mold, restoring fer 

 tility.&quot;* 



In one part of the pine forest I saw the Liquidambar tree 

 growing vigorously fifty feet high, with a bark resembling cork. 

 The bird of brightest plumage was the one called the red bird, 

 or red cardinal (Loxia cardinalis), which has a full, clear, and 

 mellow note, though no variety of song. It frequents bushes, in 

 the neighborhood of houses, where it comes to be fed, but will 

 not thrive in captivity. One day, a son of Mr. Couper s brought 

 us a hen cardinal bird and a wild partridge, both taken unin 

 jured in a snare. It was amusing to contrast the extreme fierce 

 ness of the cardinal with the mildness and gentleness of the 

 partridge. That insects, birds, and quadrupeds, of the same 

 genera, but of distinct species, discharge similar functions in 

 America arid Europe, is well known. My attention was called 

 here to some thorny bushes, on which the shrike or loggerhead 

 (Lanius ludovicianus) had impaled small lizards, frogs, and 

 beetles, just as I have seen mice and insects fixed on thorns by 

 our English shrikes. Here, also, the marshes near the river are 

 frequented by the belted kingfisher (Alcedo alcyori), resembling 

 * Liebig s Organic Chemistry, pt. i. ch. 8. 



