ORIGIN OF LIFE UPON THE EARTH 179
release of energy, which invariably takes place in the presence of oxygen.
On tixe other hand, the lesser components of organic compounds are the XExetallic elements with positive ions, such as potassium, sodium, cal- cium, amd magnesium, calcium combining with carbon or with phos- ph^nxs as the great structural or skeletal builder in animals. There is also so much carbonaceous protein in the animal skeleton that in animals caleiiaxm takes the place of carbon in plants only in the sense that it reixice* the proportion of carbon in the skeleton : it shares the honors witlx c*«irbon.
Xxx general the electric action and reaction of the non-metallic and tte m.ctallic elements dissolved or suspended in water is believed to be the source of all the internal functions of life, which are developed aliv^y s in the presence of oxygen and with the energy either of the heat of tlx^ earth, or of the sun, or of both the heat and light of the sun.
CJosMic Pkopebties and Life Functions of the Chief Life
Elements
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��*oth the time and the mode of the origin of life is a matter of pure ^I^^^^xlation, in which we have as yet no observation or unif ormitarian f^^^oxing to guide us, for all the experiments of Biitschli and others to _ -"^^^^.te the original life process have proved fruitless. We may, how- put forward four hypotheses in regard to it, as follows: ^^Irst: we may advance the hypothesis that an early step in the "l^^-^zation of living matter was the assemblage one by one of several -» **lxe ten elements essential to life, namely, hydrogen, oxygen, nitrogen, jj^ '^^jhorus, sulphur, potassium, calcium, magnesium, iron (also per- ^j^ t^^ silicon), and carbon, which are present in all living organisms with ^w exception of some of the most primitive forms of bacteria, which
^ ^^ lack carbon, magnesium, iron and silica. Of these the four most xffVrportant elements were obtained from their previous combination in ■^ater (HjO), from the nitrogen compounds of volcanic emanations or from the atmosphere,^* consisting largely of nitrogen and from atmos- pheric carbon dioxide (CO2). The remaining six elements, phosphorus, sulphur, potassium, calcium, magnesium and iron, came from the earth. Second : whether there was a sudden or a more or less serial group- ing of these elements, one by one, we are led to a second hypothesis that th^ were gradually bound by a new form of mutual attraction whereby the actions and reactions of a group of life elements established a new form of unity in the cosmos, an organic unity or organism quite distinct from the larger and smaller aggregations of inorganic matter previously held or brought together by the forces of gravity. Some such stage of
82 Ammonia is also formed bj electrical action in the atmosphere and unites with the nitric oxides to form ammonium nitrate or nitrite: these compounds fan to earth in rain. — ^F. W. Clarke.
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