IMMUNOLOGY AND SELF-SAVING CATALYSTS 151 



may also be a help, as is the case in the Kahn test for syphilis. 24 

 The simple physico-chemical principles involved in immunology 

 extend to many other fields, as might be expected. F. R. Lillie 2 "' 

 found that seawater in which sea-urchin eggs had stood for a while 

 ("egg-water"), will agglutinate the spermatoza of the same species, 

 though the agglutinization is spontaneously reversible, seldom last- 

 ing over an hour. The phenomenon is observed in all echinoids, 

 in many molluscs, and in some annelids. The substance respon- 

 sible is called fertilizin, and A. Tyler found 20 that it comprises 

 part or more probably the whole of the gelatinous superficial 

 coat of the egg, which swells and slowly disperses, but which can 

 be quickly dissolved in acidified seawater of pH 3.5 to 4.5. "Egg- 

 water" also activates sperms. As evidence of this fact Dr. E. E. 

 Just demonstrated to me at Wood's Hole (1925) that if a small 

 dish in which a female Nereis has been floating were rinsed out 

 several times with fresh seawater and then filled, a male Nereis 

 dropped in will immediately shed its sperm. 



Fertilizin reacts with a substance termed anti-fertilizin which 

 can be extracted from the sperm surface by acidified seawater, 

 which is of interest in connection with the mode of development 

 of the sex glands. Curiously enough, the surface of the egg from 

 which the fertilizin has been removed also furnishes a substance 

 showing the same behavior and immunological specificity as anti- 

 fertilizin. Commenting on the fact that these substances react 

 with one another in the specific and complementary manner of 

 antigens and antibodies, Tyler suggests application of this notion 

 to explain the auto-agglutination of bacteria and the production of 

 bacterial antibodies. 



"The finding of two mutually complementary substances leads to 

 the expectation that more may be found deeper within the cell. This 

 view may then be expanded into a general theory of cell structure; 

 namely, that a cell is a mosaic of substances that are mutually com- 

 plementary (i.e., capable of combining with one another in the manner 

 of antigen and antibody) substances which are actually in combination 

 with one another in regions where they adjoin. The compounds 

 would be represented by the various membranes, such as the cell 

 membrane, nuclear membrane, nucleolar membrane, vacuolar mem- 

 brane, etc., which in turn keep the complementary substances apart." 



This view is consonant with the establishment of interfacial films, 

 which, as the work of Harkins, Langmuir, Adam, Freundlich and 

 others has shown, may be polymolecular and more complicated than 



