76 THE PROTEOMORPHIC THEORY AND THE NEW MEDICINE 



Loss AND GAIN THROUGH THE DIVISION OF LABOR 



But the reader who would clearly apprehend the bearings of 

 the theory of immunity thus exposited must on no account fail 

 to note the exact terms of this definition just given. The anti- 

 toxins, in this view, are produced by various and sundry of 

 the body-cells, because these antibodies are evoked in response 

 to the coming of toxins that are relatively simple nitrogenous 

 compounds. When, however, the antigen that comes is not a 

 by-product of protoplasmic activity, but the protoplasm itself 

 as evidenced in the body of a bacterium or in molecules of un- 

 broken protein in any form, the case is quite altered, because the 

 body-cells in general are not adapted to absorb such materials. 

 Their location in the body, shielded by encompassing walls of 

 skin and mucous membrane, puts them out of contact with such 

 crude raw materials, the transformation of which has been turned 

 over to an especially adapted apparatus known as the digestive 

 system. 



Each cell must retain the capacity to take food ; but it may 

 have lost the capacity to imbibe this food in a crude or undi- 

 gested form. 



Such is indeed the condition of the specialized cells of the brain 

 and muscles and of the parenteral organs in general. The pen- 

 alty of their specialization is that each of them, while gaining in 

 one feature, has lost in various others. The single speck of 

 protoplasm that constituted the entire structure of the primor- 

 dial protozoal ancestor was at once stomach and muscular sys- 

 tem and circulatory apparatus and brain. But in the developed 

 organism each individual cell retains only the faint reminiscence 

 of each type of function except the one for which it has been 

 especially developed ; and this one it can carry out in exaggerated 

 fashion. The particular cells that have made themselves mas- 

 ters of that department of the work which has to do with the 

 ingestion of food and the splitting up of proteins is called the 

 digestive apparatus ; and its work is supplemented, we have found 

 reason to believe, by the leucocytes and erythrocytes. 



But when, as occasionally happens through inadvertence, a 

 considerable quantity of protein in the unbroken form makes its 

 way into the circulation and comes thus (unmodified) in contact 

 with the body-cells in general, it is as useless to these cells as 

 if it were composed of utterly unassimilable materials. 



The proof of this is that proteins thus introduced in quantity 

 are excreted unchanged through the kidneys. The leucocytes and 

 erythrocytes, to be sure, deal with part of this foreign protein; 

 but their capacity is limited, and beyond that nothing remains but 

 to eliminate the foreign substance as rapidly as possible. In 



