All spider poisons powerfully affect the nervous system (See tarentula, Mygale, etc).
All symptoms of Aranea are characterized by periodicity, and coldness, and great susceptibility to dampness. It is the remedy for the constitution favorable to malarial poisoning, where every damp day or place favors chilliness. Patient feels cold to the very bones. Coldness not relieved by anything. Feeling as if parts were enlarged and heavier. Wake up at night with hands feeling twice their natural size. Spleen swollen. Hydrogenoid Constitution, i.e, Abnormal sensitiveness to damp and cold, inability to live near fresh water, lakes, rivers, etc, or in damp, chilly places (Nat. Sulph. Thuja).