HALLUCINATIONS.
Subjective cerebral impressions projected as real. Rabies. Toxins. Poisons. Essential oils. Chloroform.
Hallucinations are subjective impressions which the animal supposes to be real. The disorders in his brain are projected outward and become to him real objects and occurrences.
They may arise from the presence and proliferation of microbes in the brain as in rabies in animals. They may proceed from poisoning of the brain by toxins as in anthrax.
They may be developed, in dogs especially, by the action of certain essential oils on the cerebral cortex. The first two classes will be considered with those special diseases. The mental disorders from drugs have been studied experimentally by Cadeac and Mennier, and may be noticed in this place.
Lavender, fennel and angelica produce in the dog a condition of extreme terror, and overcome all disposition to exercise self-defense.
Mints and origanum induce hallucinations of odor. The dog seeks around with head and nose elevated, sniffs the air, moves cautiously, fixes his eye on some phantom object, and starts to hunt imaginary game. The love of catmint seems to amount to a mania in the feline animal.
Kidney vetch evidently causes a sensation of itching or formication; the dog bites the hair of the tail, the hind limbs or the flank as if to destroy fleas or other vermin.
Dogs under chloroform have sought to hunt, and stallions under ether have shown generative excitement with erection of the penis and movements of coition.