166 EXPERIMENTS RELATING TO 



the impregnated ova, when tolerably advanced, 

 may be kept for many days in air, saturated 

 with moisture, without suffering loss of vitality, 

 or having their power sensibly impaired. Se- 

 condly, in accordance with the foregoing, that, 

 in rainy weather, they will bear exposure to the 

 atmosphere, if placed on moss or other moist 

 plants, so long as three days, without detri- 

 ment. Thirdly, that they are capable of 

 bearing a reduction of temperature to thirty- 

 two degrees Fahrenheit, i. e., to the freezing 

 point of water, and may be attached to ice, 

 and included in ice, provided they are not 

 themselves frozen, without losing their vitality. 

 Now, reasoning from these results, there seems 

 little difficulty in imagining how a certain 

 diffusion of the species may be accomplished, 

 whether, as hinted at when we last conversed 

 on the subject, by means of water-fowl, the 

 ova adhering to their feet, beak, or plumage, 

 or of other erratic animals, or, to offer an- 

 other conjecture, even by means of travelling 

 masses of ice, glaciers, and icebergs. This last 

 conjecture may seem far-fetched ; but reflecting 

 on the erratic masses of rock, so widely scattered 

 from their original site, conveyed, there is good 



