Immunologic reactions as well as tryptic action are strongly influenced by possibly extra‐terrestrial radiations, when such reactions are performed at a liquid‐solid interface. These radiations, which could be called soft cosmic radiations until more is known about them, affect the long‐range order of the superficial nickel layer of the solid phase upon which the antigen molecules are anchored. On account of a solar radiation, stopped by 3.5 cm of lead, the course of immunologic reactions exhibits an exact 24‐hr periodicity.