178 COLLX CLOUT'S CALE.XDAR. 



Tndcccl.that is the rule with ihc vast majority of species, 

 animal or vc^^ctablc. There arc a few whiciv. lil<e man, 

 the Colorado beetle, and the Canadian pond-weed, are 

 raj)idly increasinj^ and overrunning; the world ; there 

 are a few others which, like the j^reat auk, the beaver, 

 and the edelweiss, are rapidly dyini;' out before their 

 enemies. lUit by far the greater number seem to con- 

 tinue absolutely invariable from >car to year, at least 

 within the ran^c of ordinary human observation. Out 

 of 40,000 seeds of one common Kn^lish wecil, only a 

 sin^dc seed on an average produces a full-grown plant 

 every season. 



