BARBITAL NARCOSIS AND HYPOTHERMIA IN PIGEONS

¹ From the Department of Physiology and Pharmacology, University of Missouri, Columbia, Missouri

1. Intra-abdominal injections of barbital produced in pigeons a definite series of changes in position and muscular activity, terminating in a fairly uniform and usually much prolonged narcosis.

2. This narcosis lasted from two to twelve days in birds recovering, and from one to seventeen days in those receiving fatal doses. In general the duration of the narcosis varied with the amount of barbital given below 300 mgm. per kilo of body weight.

3. These injections of barbital also produced a rapid and pronounced lowering of body temperature of pigeons, which averaged 0.8° during the first fifteen minutes, 1.7° during the first thirty minutes and 2.8°C. during the first hour.

4. The minimum body temperature in the first stage was recorded about two and one-half hours after the injection of barbital and the depression averaged 3.8°C. at that time.

5. The minimum body temperature during the entire period of barbital narcosis appeared in the first eight hours in over half the cases observed, but was delayed in some for forty-eight hours or more.

6. Compared with control pigeons which were given neither food nor water for twelve days pigeons in barbital narcosis maintained a distinctly lower body temperature and lost weight at a slightly slower rate.

7. The minimum fatal dose of barbital given intra-abdominally was found to be between 225 and 250 mgm. per kilo of body weight for adult pigeons.

8. Pigeons were more sensitive to barbital than cats, dogs, rabbits or frogs, although the depressions of body temperature produced in pigeons were not as great as those reported for some mammals.

9. Satisfactory surgical anesthesia in pigeons was not obtained by the use of barbital alone.