"This study was conducted in the following manner. First of all: investigation of the lethal concentrations 50 on male and female animals of various species, then study of the cutaneous causticity and long-term chronic intoxications carried out on different groups of animals.

The product utilized for this experimentation had the following characteristics:

boiling point: b.p: 47.6' under 760 mm of mercury;
melting point: m.p.: -35'C;
density: D4: 1.57;
weight of a liter of saturating vapors at b.p.: 7.38 g;
density of vapor compared to air: 5.73.

In gas chromatography, only the presence of a slight peak corresponding to an impurity in proportions well below 1% was discerned.

I. - Determinations of the Lethal Concentrations 50 on various animal species.

These experimentations were carried out in tight cages of approximately 140 l equipped with a ventilator.

The product vapors were dispersed in the atmosphere of the cage, evaporating a predetermined weight of solvent by contact with a quartz condenser.

The evaporation temperature was always maintained at a value slightly below the boiling temperature of the product studied, in order to avoid possible decompositions.

The evaporation times never exceeded 10 min.

We voluntarily limited the period of exposure to 2 hr, for the relatively reduced volume of our cages exposed the animals, beyond this time, to a substantial confinement of the atmosphere, the effects of which could have been ascribed to the solvent.

The animals were continuously observed during experimentation, and the surveillance continued for 2 weeks following the exposures. After this time, the surviving animals were destroyed."

"II. - Realization of Chronic Intoxications

Chronic intoxications were realized by subjecting animals daily, two hours a day, five days a week, to trichlorotrifluoroethane contents of approximately one-tenth of the lethal concentration 50; thus, one lot of six Wistar albino rats of male sex was exposed for 24 months to a concentration of 12,000 ppm, while a lot of another six control rats served as comparison and was subjected to the same controls."

"Furthermore, a similar experiment was carried out on rabbits, utilizing two different races: Fauve de Bourgogne and Blanc de Bouscat (albinos).

"In this case, two animals were exposed in a cage of 1 m^3 for two hours a day, 5 days a week, in a concentration of trichlorotrufluoroethane of 11,000 ppm.

In order to determine possible electroencephalographic alterations, certain animals were previously trephined in order to implant electrodes permanently (1) and subjected to exposure after their complete recovery (15 days to 3 weeks after the operations). Behavior of these animals was compared to that of control animals also trephined and others having undergone no operation."

"(1) The technique of permanent implantation of the electrodes is that utilized ordinarily in neurophysiological laboratories, the electrodes being connected to a plug attached to the skull of the rabbit by dental cement.

The exposure times of the animals are indicated in table III on p. 7."

Fauve de Bourgogne Rabbits