 reaction adren cortex control experiment hypothermia stress reaction caus hypothermia studi rabbit subject control hypothermia immers icebath anim re-warm anesthet anim pentobarbiton sodium nembut intraperiton case ether anesthesia stress reaction produc pentobarbiton studi anim ether anesthesia three anesthesia three rabbit refriger variat distribut amount adrenocort lipid serv indic evalu stress reaction hypothermia test occur chang distribut amount cortic lipid denot stress reaction brought hypothermia rabbit barbitur inhibit stress reaction attribut partli test anim partli fact shiver extent occur hypothermia experi 