68 THE ORIGIN AND EVOLUTION OF LIFE 



lack magnesium, iron, and silica. Of these the four most im- 

 portant elements were obtained from their previous combina- 

 tion in water (H2O), from the nitrogen compounds of volcanic 

 emanations or from the atmosphere' consisting largely of 

 nitrogen, and from atmospheric carbon dioxide (CO2). The 

 remaining six elements, phosphorus, sulphur, potassium, cal- 

 cium, magnesium, and iron, came from the earth. 



Second: Whether there was a sudden or a more or less serial 

 grouping of these elements, one by one, we are led to a second 

 hypothesis that they 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, an individual or organism quite distinct from 

 the larger and smaller aggregations of inorganic matter pre- 

 viously held or brought together by the forces of gravity. 

 Some such stage of mutual attraction may have been ancestral 

 to the cell, the primordial unity and individuality of which we 

 shall describe later. 



Third: This leads to the hypothesis that this grouping oc- 

 curred in the gelatinous state described as "colloidal" by 

 Graham.'- Since all living cells are colloidal, it appears prob- 

 able that this grouping of the "life elements" took place in a 

 state of colloidal suspension, for it is in this state that the life 

 elements best display their incessant action, reaction, and 

 interaction. Bechhold^ observes that "Whatever the arrange- 

 ment of matter in living organisms in other worlds may be, it 

 must be of colloidal nature. What other condition except the 



' Ammonia is also formed by electrical action in the atmosphere and unites with the 

 nitric oxides to form ammonium nitrate or nitrite; these compounds fall to earth in rain. 

 — F. W. Clarke. 



^ Over fifty years ago Thomas Graham introduced the term "colloid" (L. colla, glue) 

 to denote non-crystalloid indiffusible substances, like gelatine, a typical colloid, as dis- 

 tinguished from diffusible crj'stalloids. Proteins belong to that class of colloids which, 

 once coagulated, cannot, as a rule, be redissolved in water. 



^ Bechhold, Heinrich, 1912, p. 194. 



