An attempt to produce a unilateral smoking dog using the contralateral lung as control.

Left mainstem bronchus as it is transected at carma. FIGURE 1B: Left main stem bronchus open at distal end plus tracheal end closed. Insert shows teflon tube being anastomosed to distal left bronchus. The carcinogenicity of tobacco tar for the skin of mice was proved by Wynder, Graham, and Croninger in 1953.' Rockey and co-workers found that tobacco tar applied directly to the bronchial mucosa of dogs produced squamous metaplasia in 17 days. The same group stated that the ideal type of experimental exposure would be one that more closely simulated human exposure.' This, they state, would involve exposure of animals through some unique smoking device to tobacco smoke. We have attempted to produce a unilateral smoking dog. The dog smokes cigarettes through a broncho-cutaneous fistula; the contralateral lung, not exposed to cigarette smoke, serves as a control. The first method used was that of anastomosing a two inch piece of % crimped teflon to the distal end of the left bronchus. Using sterile operating room technique and sodium pentothal anesthesia, the left 'Supported by the