340 MATERIAL RESOURCES OF LIFE. 



undefined impression that the carbonic acid of the air is just an impurity, 

 tolerated because there is only a little of it, but an impurity that it were 

 as well to be rid ot altogether. Now, if the redundant resources of life 

 were at our human disposal, we might be in danger, some day, in the sheer 

 forgetfulness of self-regard, of throwing away as an impurity the verj^ 

 foundations of sustenance. Some one, perhaps, would set forth that this 

 gas when not diluted is immediately fatal to human life; another would 

 declare, "Once a poison, alway a poison;" and another would ask why we 

 should imperil our own health for the sake of the plants. 



Oxygen was named next, among the primary resources, redundant in 

 supplj^. It is a prominent constituent of all living tissues, forming seventy- 

 two parts in a hundred of Ihe human body with its fluids. It is taken in 

 two conditions: first, in combination, chiefly by the plants; second, in the 

 elemental state, by animals. In combination, it is taken by the plants trom 

 carbonic acid gas, just noticed as a source of carbon; from water, to be con- 

 sidered as a source of hydrogen; and, in smaller quantities, from a consid- 

 erable number of other substances. The greater part of the oxygen in 

 animal tissues is obtained in the products elaborated by the plants. 



But for all animal life the most imperative demand is for oxygen in the 

 elemental state. 



The other elemental resources are available only in their compounds; 

 oxygen does its best service when alone. The others serve life as materials 

 for its bodily tissues; oxygen has an additional duty, the maintenance of 

 operations giving warmth and strength. The activities of life consume va- 

 rious materials, but most constantly of all they demand a raw material of 

 inorganic nature, a simple material in its primitive condition. This supply 

 of elemental oxygen, a necessity for all animal life, is a necessity that is 

 imminent in direct proportion to vital activity, and for man is absolutely 

 imperative. When supplied with oxygen, we can subsist days without 

 other food; when deprived of oxygen, life fails in a few minutes. It is 

 scarcely a figure of speech to say that the breath is the life. The energy 

 of ox5^genation is told in every stroke of the heart. The food that is eaten 

 does not raise an iota of bodily strength without the help ot the pound 

 and a quarter of pure oxygen that is daily inhaled. To breathe poorly is 

 to faint; to eat richly and breathe poorly is to suffocate and perish. 



The supply of elemental oxygen is certainly impartial and bountiful 

 without reservation. It is more than given — it is pressed upon us; to es- 

 cape from it is a work of toil and difficulty. No one is poor from want of 

 it, or rich from gain of it. Were it furnished for pay, all that a man hath 

 would he give for an hour's supply of it. The poor, taken together, fare 

 best in its use; while the Avealthy, in their elaborate contrivances to exclude 

 the cold and wet and wind and glare of the weather, can make but slight 

 impediments to its distribution. 



One other element we were to inquire of, among the redundant mate- 

 rials: the unit of chemical measures, hj^drogen. As light as it is, it makes 



