130 Rev. P. Keith on the ComUdons of Life. 



exceptions are the most striking; — not in the department of 

 Fishes, though their element is even the water; but in that of 

 the Amphibia. Live toads, snakes, and hzards have been 

 found imbedded in sohd masses of stone, or of coal, at a great 

 depth below the surface, and without any possibility of the 

 access of air*. They are facts occurring about as often, and 

 are about as well authenticated, as the sight of a mermaid. 

 We cannot well refuse our assent either to the one or the 

 other; and yet we cannot give it without a sort of sceptical 

 reluctance. Yet if the fact in question is anything different 

 from that of a long protracted hybernation, we are altogether 

 without the means of accounting tor it. 



Temperature. — The pha?nomena of life have never yet been 

 exhibited except within a certain and limited range of tempe- 

 rature. Too great a degree of heat, or too great a degree of 

 cold, is equally injurious to it. At a very low temperature, 

 as towards the poles, plants and animals aie often frozen to 

 death. At a very high temperature, as at the equator, they 

 are apt to perish through excess of heat. But they have the 

 capacity of preserving their due temperature under the influ- 

 ence of many opposing causes. In the midst of the frosts and 

 snows of winter, plants maintain a temperature which is always 

 above that of the surrounding atmosphere ; and even under 

 the burning heat of a vertical sun their temperature is never 

 raised very high. But different plants affect different tempe- 

 ratures, and you cannot well naturalize them in climates to 

 which they are not indigenous. You may indeed have all 

 varieties of them in the same latitude ; but it shall be in the 

 conservatory, or in the hot-house, and if not, it shall be at 

 different altitudes. Tournefort noticed this fact, in the case 

 of the plants growing on Mount Ararat; and Humboldt gives 

 us a similar account of the vegetation of the mountainous dis- 

 tricts of South America. In ascending the Andes within the 

 tropics, oranges, pine-apples, and all manner of delicious fruits 

 and vegetables, are found on the lower grounds. Maize, 

 plantains, indigo, cacao, at an altitude of from 3000 to 5000 

 feet. Cotton, coffee, sugar, at the same altitude, but ascending 

 still higher. Wheat, and other European grains, together 

 with the oak and other forest trees, at the altitude of from 

 6000 to 9000 feet. The pine still lingers at an altitude of 

 13,000 feet above the level of the sea. From 13,000 to 15,000 

 feet, you have grass and lichen, which last creeps up still 



Nidus Avis, Monotropa, and Orobanche, are destitute of true leaves, and 

 are consequently incapable of drawing sustenance from the atmosphere. 

 These latter plants, therefore, appear to present real exceptions to the rule 

 here vindicated by Mr. Keith. — Edit.] 

 • Phil. Mag. March 1S17. 



higher. 



