56 THE PROTEOMORPHIC THEORY AND THE NEW MEDICINE 



THE PRIMORDIAL LEUCOCYTE 



In such a view, it would appear that the leucocyte is a rela- 

 tively unspecialized cell, the least-modified present-day repre- 

 sentative of the prototypal single-celled ameboid organism from 

 which the entire body has developed. It is consistent with this 

 view that the leucocyte should have retained the primitive func- 

 tions of digestion and assimilation of proteid bodies as its essen- 

 tial task in the developed body. 



It is not unlikely, then, that in reviewing the conditions which 

 determine the relations of the protozoan to its environment we 

 may gain an insight for the better interpretation of some of the 

 activities of the leucocyte, its lineal descendant. 



If, then, we go back to the evolutionary beginning, and review 

 in imagination the conditions of the time when the only living 

 organisms were single-celled ones, we must think of our primor- 

 dial ancestor as a protoplasmic cell endowed with a curious ca- 

 pacity to absorb certain materials from the environment, and 

 through assimilating them to grow ; endowed, also, in the pur- 

 suance of this mission, with capacity to respond to impressions 

 received from the environment. 



The protoplasm making up the body of this primitive organism 

 was a compound of carbon, hydrogen, oxygen, and nitrogen, with 

 minute quantities of a few other chemicals, notably sulphur; 

 which was liquid in character, but differed in its essential qual- 

 ities from the inorganic substances about it, chiefly, we may 

 suppose, because of the exceedingly intricate character of the 

 relations of the very large number of atoms that entered into 

 each molecule. The physical principles that determined the rela- 

 tions of this protoplasmic solution with other solutions in which 

 it might be immersed were determined in accordance with the 

 laws of capillary absorption and of osmosis. 



The essential functions of the protoplasm, in virtue of which 

 it might be spoken of as a living organism, were probably con- 

 tingent on the fact that each molecule contained a large num- 

 ber of atoms of carbon, an element having four chemical valences ; 

 and a considerable number of atoms of nitrogen, an element 

 that may have either three or five valences, and which is signally 

 characterized by its unwillingness to enter into combination, and, 

 contrariwise, its exceeding desire for liberty when once it has 

 been combined, resulting in the instability of all nitrogen com- 

 pounds. Nearly all explosive compounds, it may be noted, con- 

 tain a nitrogen element. Indeed, the analogy as to composition, 

 between protoplasm and dynamite and other high explosives, is 

 striking and highly suggestive. There is one important differ- 

 ence, however artificial explosives contain enough oxygen to 



