The adjuvant effect of tuberculin in experimental sensitization to merthiolate.

When guinea pigs were sensitized to tuberculin by exposure to complete Freund's adjuvant the size of the intradermal PPD test was positively correlated to the body weigth of the animal. Old Tuberculin showed stimulating effect in a subsequent sensitization to merthiolate (thimerosal). The high frequency of delayed cutaneous allergy to merthiolate in the Swedish population is probably explained by sensitization through intradermal testing with tuberculin containing merthiolatc as a preservative.