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.