Experimental Production of Tumors by Tars from Various Foods

Abstract

In view of the successful production of tumors by crude coal tar 14 and its derivatives with known chemical composition, 1 , 2 , 3 , 4 interest has been directed to the question whether tars prepared from substances which we eat or smoke are also carcinogenic. Fukida and Kinosita 5 found that tar from rice bran is carcinogenic to the skin of mice. Kenneway 6 produced cancers and papillomas by human skin tar and yeast tar. Shibata 11 reported on the carcinogenic action of the tar from sugar. Roffo 8 found tumor growths in the stomach, liver, and cecum of rats fed on bread and milk to which was added animal fat or olive oil that had been heated to 350° C for half an hour. Widmark 13 succeeded in obtaining adenocarcinomas of breast with alcohol or petroleum-ether extract of roasted horse muscle, coffee and brown butter. LÜ, 7 Taki, 12 and Sugiura, 10 etc., produced tumors on mice by tobacco tar. Roffo 9 was able to identify the presence of 1-2 benzpyrene, a carcinogenic hydrocarbon, in tobacco tar.

The following experiment was carried out to find whether tars from certain common food articles also have carcinogenic properties.

Material and Method. The material consisted of polished rice, pea flour, soybean, casein, wheat gluten, whole wheat, corn, cabbage, pepper, beef, and pork. Each of these, in dry form, was placed in an iron retort to about one-half of its full capacity and was then heated on a strong gas flame for destructive distillation. The distillate was collected in a water-cooled receiver. To remove the small amount of water present, the distillate was shaken with an equal part of chloroform.