ANTIBODY 105 



always inversely proportional to the pathogenic action of 

 antigens. 



We know that the substance to which the role of normal 

 antibody belongs can fulfil different functions which are 

 more or less important in the normal life of the cell. This 

 "substance" may be in an organ of sense or a function of 

 nutrition or of reproduction or finally a substance of reserve 

 and in each the immunizing excitation or the lesion will 

 be manifested by its different effects on the function of 

 the particular tissue and on the general economy. We know, 

 further, that it is not always the same cells of an organism 

 which are sensitive to the action of an antigen. Where, for 

 example, it is the cells of the central nervous system which 

 are exclusively or more particularly sensitive to the action 

 of an antigen, the production of antibody is very precarious 

 if not absent, probably because the nerve cells do not recup- 

 erate and because the excitation even of this tissue, however 

 slight, always results in profound disturbances of the general 

 economy. We may conclude that the less important the 

 role of the particular tissue, the easier and less harmful will 

 be the process of immunization. This is almost all that 

 we can say as to the biologic origin of antibodies. 



As to their physicochemical nature, we know that anti- 

 bodies are one of those components of "antiserum" which it 

 has been quite impossible to isolate by dialysis. We assume, 

 at least tentatively, that they are colloids, but we cannot 

 prove it directly. The example of the transformation of 

 coagulated arsenobenzene when one adds to the molecules 

 an acid or base which holds the colloidal granules in suspen- 

 sion in water; the redissolution of the coagulum as well as 

 the dislocation of the colloidal granules by a sort of sulpho- 

 nation will serve to prove that antibodies may be something 

 much more simple than a colloid, but if this is possible for 

 arsenobenzene it seems today too simple for antibodies and 

 all the other antigens. Let us be content for the moment 

 to remember the essential simplicity of the reactions which 

 determine the transformations of arsenobenzenes and to 

 hope that later researches will help us to recognize the 

 nature and the mechanism of biologic antigens. 



