FURTHER OBSERVATIONS ON THE EFFECT OF BENZENE ON A STRAIN OF MYELOID CHLOROLEUKEMIA IN MICE AND ON CHANGES PRODUCED IN THE LEUKEMIC CELLS BY THE CHEMICAL

Oral administration of 5 mg. of benzene six times weekly to 46 mice that hadbeen injected 24 hours before with the cells of the myeloid chloroleukemia 1394,considerably prolonged the survival of the animals, and in 16 of these mice itseemed to prevent the development of the disease. The spleens of the animals sotreated increased in size at a much slower rate than those of the untreated animals,and the leukemic infiltration of the organs was delayed.

Five mg. of benzene given in a similar manner to mice with advanced chloroleukemia likewise prolonged the survival time of the mice and also slowed therate of increase of the size of the spleens; 25 mg. given five times in a 6 day periodto mice with this leukemia brought about a marked reduction in the size of thespleens. Further treatments slowed the rate of enlargement of the spleens andsurvival was prolonged.

In 8 mice bearing subcutaneous tumors composed of the cells of the chloroleukemia the oral administration of 25 mg. of benzene five times in a 6 day periodfollowed by 5 mg. given six times weekly brought about the disappearance of thelocal tumors as determined by palpation, but in 6 mice the tumors recurred andkilled the animals. Microscopic examination of tumors of mice treated with benzene showed advanced degenerative changes in leukemic cells.

Note: The authors with to thank Miss Pauline Pope, Miss Mary Boon, and Miss Lucille Wolf for theirtechnical assistance.