The duration of incubation for icteric viral hepatitis appears to be shorter for fresh blood, serum, and plasma than for stored serum or plasma, pooled or unpooled. More than half of the cases of serum hepatitis from blood occur prior to the 60th day and three fourths before the 90th day.
It has become evident also that one may extend the incubation period for infectious serum and plasma almost at will, especially by the use of ultraviolet light or by storage of liquid plasma or serum at temperatures between 20 and 35 C for three months or longer. Eventually, these extensions of icteric serum hepatitis reach "infinity," in that no cases of serum hepatitis are observed.
It is the purpose of this paper to present data from several sources in support of these statements and to discuss their possible relationship to the Australia antigen. In general, the longer the duration