IT WOULD TAKE one into too controversial a field to attempt to cover all the allergic manifestations of the central nervous system which might be attributed to the hypersensitive state. I shall, therefore, omit from consideration migraine, histamine cephalalgia, Ménière's syndrome, epilepsy and certain convulsions of infancy, which have all been charged to allergy by one or another investigator.
My remarks will be confined to an analysis of the cerebrospinal effects occurring in serum sickness and from serum allergy1. The allergic manifestations resulting from the parenteral injection of foreign serum lend themselves to accurate appraisal. The time of entrance of the otherwise innocuous substance can always be ascertained; the material is not complicated, nor does it possess primary toxicity when properly prepared.
Consideration of allergic encephalopathies from smallpox or rabies vaccines, drugs and antibiotic substances is somewhat complicated because of the primary toxicity of drug and antibiotic substances on