Anaphylaxis in the Normal Unanesthetized Dog

During the course of an investigation carried out in this laboratory, anaphylaxis was induced in 61 normal unanesthetized dogs. Since references in the literature to anaphylaxis produced under these conditions in a large series of dogs are meager, it was deemed advisable to record our results.

The dogs were sensitized by injecting 5 cc. of normal horse serum subcutaneously and 5 cc. intravenously. After a 16 day incubation period the animals were given the provocative dose of horse serum consisting of 10 cc. administered intravenously.

Evaluation of the anaphylactic reaction in unanesthetized animals depends on the observation of symptoms and not on the determination of measurable responses; so it is subject to individual interpretation. This difficulty was overcome as far as possible by dividing the reactions into several classes according to their intensity, and then arbitrarily designating certain sets of symptoms as characteristic of each class. Thus all reactions are described as either slight, moderate, moderately severe, or severe. In a slight reaction the animal shows only slight transitory symptoms, little or no disturbance of respiration, never loses interest in his surroundings, and will eat meat 5 minutes after the injection. In a severe reaction the animal can not be aroused from the stuporous state in which he lies on his side and manifests marked respiratory difficulty. Moderate and moderately severe reactions are graded between these extremes. In a moderate reaction the animal, although weak and ataxic, is able to move about unsteadily under his own propulsion. In a moderately severe reaction the animal sinks to the floor but can be aroused from his stupor and made to stand on his feet.