Abstract
Labyrinth destruction in the rabbit as well as in other animals produces a marked temporary and a less marked permanent decrease in muscular tonus. If body temperature is in any way dependent upon the heat production of tonic contractions these characteristic tonus changes should be accompanied by equal and parallel changes in the body temperature. 1
Four or 5 entirely successful operations have been performed with identical post-operative symptoms. The tonus modifications are immediately evident, but the development of the hypotonia continues for about 2 hours, during which time the animal lies on its ventral side (an unusual position for a rabbit) in a completely relaxed condition, unable to maintain any antigravity posture, but permitting the elicitation of reflexes. This condition, however, is transient and within 2 to 3 hours the tonus has increased until a sitting and finally a standing position is regained. The animal then makes occasional progressive movements, but with evidence of great muscular weakness.
The temperature changes follow the same course. There is an immediate fall, in the example given, from a normal of 39.5° C. to 35.4° C. followed by a further gradual decrease to 34.6° at the time of greatest tonus loss. As the tonus again increases, the temperature rises until it reaches 38.3° C. about 10 hours after the operation. It later drops one degree and remains near 37.5° C. until the rabbit is killed.
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