The salts of the natural polyamines, protamine sulphate, clupeine sulphate, spermidine phosphate, putrescine dihydrochloride and spermine diphosphate, and of the synthetic poly-L-lysine hydrobromide (mol. wt 85 k) and poly-L-arginine hydrochloride (mol. wt 50 k) were tested for their effect on film