LIMITS OF LIFE. 



59 



are indeed often called infinite ; while the Bio- 

 cosmos we find circumscribed on all sides, in 

 Space, Time, Quantity. Of this fact we shall 

 take some notice in detail. 



I. In the first place, Life, as it is found on 

 our globe, exists nowhere else in the Universe, 

 as far as we know. Under the conditions 

 given by our earth, it can hardly endure on 

 any other planet, though some have thought 

 that Mars may be inhabited. Of course, there 

 can be imagined a vital activity very different 

 from ours an animal heat, for instance, 

 equal to the heat of the Sun, and the Sun has 

 been sometimes held to be an animal. Still, 

 as far as we can at present discover, Life is 

 a unique terrestrial gift. 



In the next place planetary Life regarded as 

 a whole, is an exceedingly small part rela- 

 tively not more than a microscopic point- 

 of the total amount of matter of our globe. 

 One scientist has estimated that all living 

 organisms taken together the sum total of 

 Earth-life to be not more than one ten- 

 millionth part of the material whole of our 

 terrestrial sphere. This estimate does not 

 take into account the physical universe out- 

 side of the Earth-ball, which is also non-vital, 

 as far as we can tell. As to quantity, there- 

 fore, all Life, conceived together in mass, is 



