NATURE IN MOTION. 53 



compelled to take along with these eminently useful 

 grasses their inseparable companions, a whole rabble of 

 weeds, thorns, and thistles. Most of these, as now found 

 in our fields, carne, without doubt, with the cerealia. In 

 still larger numbers, however, and without the agency of 

 man, certain other plants attach themselves to the lord 

 of creation and follow him wherever he goes, and builds 

 himself huts. These seem not to be bound to their 

 kinsfolk, the grains and grasses, but to man's own im- 

 mediate home ; they settle with never-failing punctuality 

 around his house, near to his stable, or luxuriate on his 

 dunghill. Travellers can thus trace, as the celebrated 

 Augustin St. Hilaire did in Brazil, by the mere presence 

 of weeds, even in the midst of a desert, the place of 

 abandoned and utterly destroyed settlements. Stranger 

 still is it, that the different races of men have different 

 kinds of weeds following in their wake, so that a careful 

 observer can, in travelling, see at once, by merely no- 

 ticing the prevailing weeds, whether Europeans or Asiatics, 

 Germans or Slaves, Negroes or Indians, have dwelt at 

 certain places. It was not without good reason, then, 

 that some of our Indian tribes called the common plain- 

 tain in their language " the white man's footstep ;" a 

 simple but distinct vetch marks in like manner, even now, 

 long after the entire abandonment of the land, the for- 

 mer dwelling places of Norwegian colonists in Greenland. 

 Historians, also, may thus learn yet many a lesson, even 

 from weeds, as to the direction and length of the great 

 migrations of the human race. One of the most remark 

 able instances of the kind is perhaps the almost universal 



