8 ELEVENTH REPORT. 



greater part of the task of elaborating the organized food-stuffs, as well as 

 that of elaborating the dissolved food-stuffs of the sea." 



It is very evident, from what Johnston says, that he is not thoroughly 

 familiar with the different species or classes of bacteria, and he does not 

 seem to think that it is possible that the unicellular life, as represented by 

 micro-organisims, may be responsible for shaping the elements of earth 

 into such form as may render them suitable for life forms beyond them. 

 The unicellular forms can thrive upon the simplest ingredients furnished 

 them by the sea conditions of ages ago, and it is quite possible that they 

 can give rise to such other ingredients as would be essential for the next 

 step in higher developments. 



The machinery which is able to work up the elements into groups or 

 radicles, groups into molecules, molecules into complexes, and, shall we say 

 complexes into structural entity, does not necessarily recjuire that the 

 elements, the radicals or groups be the same. The benzene ring retains its 

 identity through various and multitudinous changes in elements, radicals, 

 and groups. The facial features, the individual conditions are able to be 

 altered, but the family tie exists in the constancy of the complex which we 

 may regard as similar to the benzene ring. Ehrlich's side chain theory has 

 made it possible to move in various directions with some degree of funda- 

 mental truth still adherent in each manifestation. The development of 

 anti-bodies by the living cell or central molecular complexes, their power 

 to counteract the influence of the toxin, the production of lysins, agglutins, 

 and other bodies which are dependent upon the living body, all indicate a 

 remarkable power of adjustment; we say on the part of the cell, but is it 

 not on the part of the central molecular complex or complexes, through 

 their changing side chains? This is meagerly illustrated by the work of 

 Nuttall, who, in his investigations with precipitins was able to establish 

 a family connection among animals of a kindred nature. In other words, 

 instead of using morphological methods, he was able to verify morphological 

 methods by molecular kindredship. Among micro-organisms, this per- 

 manency of a central or molecular complex, with the possible variations 

 occuring in its side chains or groups, is vividly brought to mind by such 

 physical or chemical phenomena as are manifested by the chromogens in the 

 formation of different pigments, in photogens by the production of light, 

 in thermogens by an excessive heat accumulation, in zymogens by an ex- 

 alted production of some particular enzyme, in pathogens by the formation 

 of toxins. So far as known, in each class the necessary life functions of the 

 cell go on in the routine manner, but all of these special functions are more 

 or less subject to great variation. We are, therefore, disposed to throw life 

 functions which are absolutely essential to the cell, into the body of the 

 complex, and these secondary functions, not essential to the cell, into the 

 same category as covered bv Ehrlich's side chains. 



Our attention has been centering upon the molecular structure of the cell 

 in order to bring out its important chemical bearing upon life's development. 

 If it were possible, in this limited discussion, to expand somewhat and include 

 the physical factors involved in living matter and illustrate how they ai-e 

 applicable to unicellular life, and how they approach, in the greatest simplicity 

 possible, the dynamic principle underlying this life, there would be, doubtless, 

 much weight added to the contention that the summation of life's forces 

 is within the molecular complex of the cell. It is utterly impossible, of course, 

 to designate between physical forces and molecular or chemical forces. 

 Heretofore, we have been concerning ourselves, however, with physical 



