Observations on the development of Guerin carcinoma are reported induced in rats bу transplantation and previous prolonged lосаl anesthesia with the following compounds: quinine-urea, quinine-HCl-urea апd quininebrom-urea. lt is established that the obtаinеd with quinine-HCl-urea anesthesia accounls for the suppression of the development of the carcinoma graft. А similar but rather weaker effect is displayed bу the compound quinineurea, whereas the combination quinine-brorn-urea shows по effect whatever. It is estblished that аll three substances do not inhibit the growth of the tumor if injected after the formation of the Guerin carcinoma has occurred.