OF VITAL ACTIONS IN GENERAL. 41 



perhaps twice that number of years ago ; the wheat being different in 

 some of its characters from that now growing in the country. 



45. These facts make it evident that there is really no limit to the 

 duration of this condition ; and that when a seed has been thus pre- 

 served for ten years, it may be for a hundred, a thousand, or ten thou- 

 sand, provided that no change of circumstances either exposes it to de- 

 cay, or calls its vital properties into activity. Hence in cases where" 

 seeds have been buried deep in the earth, not by human agency, but by 

 some geological change, it is impossible to say how long anteriorly to 

 the creation of man they may have been produced and buried ; as in the 

 following very curious instance. Some well-diggers in a town on the 

 Penobscot River, in the State of Maine (New England), about forty 

 miles from the sea, came at the depth of about twenty feet upon a stra- 

 tum of sand ; this strongly excited curiosity and interest, from the cir- 

 cumstance that no similar sand was to be found anywhere in the neigh- 

 bourhood, and that none like it was nearer than the sea-beach. As it 

 was drawn up from the well, it was placed in a pile by itself ; an unwil- 

 lingness having been felt to mix it with the stones and gravel which 

 were also drawn up. But when the work was about to be finished, and 

 the pile of stones and gravel to be removed, it was necessary also to 

 remove the sand-heap. This, therefore, was scattered about the spot 

 on which it had been formed, and was for some time scarcely remem- 

 bered. In a year or two, however, it was perceived that a number of 

 small trees had sprung from the ground over which the heap of sand 

 had been strewn. These trees became in their turn objects of strong 

 interest, and care was taken that no injury should come to them. At 

 length it was ascertained that they were Beach-Plum trees ; and they 

 actually bore the Beach-Plum, which had never before been seen, 

 except immediately upon the sea-shore. The trees had therefore sprung 

 from seeds, which were in the stratum of sea-sand, that had been pierced 

 by the well-diggers. By what convulsion they had been thrown there, 

 or how long they had quietly slept beneath the surface, cannot possibly 

 be determined with exactness ; but the enormous length of time that 

 must have elapsed since the stratum in which the seeds were buried 

 formed part of the sea-shore, is evident from the accumulation of no 

 less than twenty feet of vegetable mould upon it. 



46. Numerous instances will be related in the succeeding Chapter, of 

 the occurrence of a similar condition in fully-developed Plants, and even 

 in Animals of high organization. In some of these it is a regular part 

 of the history of their lives, coming on periodically like sleep ; whilst in 

 others it is capable of being induced at any time, by a withdrawal of 

 some of the conditions essential to vital activity. In regard to all of 

 them, however, it may be observed, that the vitality can only be retained, 

 when the organized structure itself is secluded from such influences as 

 would produce its decay. Thus, the hard dry tissue of the seed is but 

 little liable to decomposition ; and all that is usually required for the 

 prevention of change in its structure, is seclusion from the free access 

 of air and from moisture, and a steady low or moderate temperature. 

 If a seed be exposed to air and moisture, but the temperature be not 

 high enough to occasion its germination, it will gradually undergo decay, 



