“…However, general toxic symptoms developed concomitantly, even when local medication was used. Lanzieri et al (1966) gave 6-MP (18 mg/kg every 3rd day) to dog to suppress the corneal heterograft reaction. Heterograft reaction was smaller during the 20th postoperative day, but subsequently it was almost the same in both the treated and untreated animals and all the grafts clouded.…”