Measurements of Fatal Doses of Chloroform in the Brains of White Rats.

Abstract

Qualitative tests. The aqueous extracts of the brains of frogs, mice, rats, guinea pigs, cats, and dogs, killed by inhaling chloroform, have all shown the presence of chloroform by the pyridine test, 1 while similar extracts from animals killed by electricity, illuminating gas, CO₂, blow on the head, and beheading, have all been negative for chloroform. In a series of 8 brains from rats killed by inhaling chloroform, the tests were made at the end of 1, 1 ½, 2, 3, 5, 6, 15 and 25 days respectively. In each case chloroform was indicated, in spite of the fact that considerable decay of the tissues had occurred. These results agree with those reported by Luedeking, 2 and Angiolani, 3 to the effect that chloroform in animal tissues persists unchanged for many days after death and decay.

Quantitative tests. The chloroform present in extracts of brains from rats killed by inhaling chloroform has been measured by the pyridine colorimetric method. Into a 1-liter dish containing a rat, a known amount of chloroform was sprayed. At the moment of death (cessation of respiratory movements) the rat was removed and its brain extracted. A dose of 0.1 cc. was sub-lethal in 35 minutes; 0.2 cc. caused death in an average of 11.2 minutes; 0.4 cc. in 5.4 minutes; 0.8 cc. in 4.3 minutes; 1.0 cc. in 3.5 minutes; 2.0 cc. in 2.5 minutes; 4.0 cc. in 1.6 minutes and 5.0 cc. or more in 1.5 minutes. The time of death bore no clear relationship to size of the animal. In Table I are given the amounts of chloroform found in brains of killed and anesthetized rats.