Document Type


Publication Date

Fall 12-21-1953


Experiments with E. Coli B. and its mutants B/l and B/l,5 showed that the cells of each mutant strain will agglutinate and precipitate in certain definite ranges of concentration of H + , Na+ and C a ++. This precipitation is reversible, and is apparently due to the neutralization of surface charge by the cations in a manner comparable to the flocculation of colloidal particles. The regions of cation concentration within which B/l and B/l,5 precipitated ware identical within experimental error; the concentration needed to precipitate these mutants is markedly less than that required to precipitate the wild-type B. This differentiation is the first one other than their difference in virus resistance to have been made.