Specific Animal Irritants.—Cantharides 92 CHAPTER XXII. Narcotics.—Neurotics, acting on the Brain and producing Sleep: Opium 95 CHAPTER XXIII. Anæsthetics.—Neurotics acting on the Brain and producing Insensibility: Chloroform—Chloral—Bichloride of Methylene—Ether—Amylene—Nitrous Oxide 102 CHAPTER XXIV. Inebriants.—Neurotics acting on the Brain and producing Intoxication: Alcohol—Nitro-Benzole—Cocculus Indicus—Fungi, &c. 108 CHAPTER XXV. Delirants.—Neurotics acting on the Brain and producing Delirium: Hyoscyamus—Belladonna—Stramonium—Datura alba—Nightshade 112 CHAPTER XXVI. Convulsives.—Neurotics producing Convulsions: Nux Vomica—Brucia—Strychnia 116 CHAPTER XXVII. Hyposthenisants.—Neurotics producing Death by Syncope: Aconite—Prussic Acid 122 CHAPTER XXVIII. Depressants.—Neurotics producing marked depression of the Heart’s Action: Digitalis—Calabar Beans—Tobacco—Hemlock 129 CHAPTER XXIX. Asphyxiants.—Noxious Gases, producing Neurotic Symptoms 134 CHAPTER XXX. Abortives.—Substances producing Abortion 137 APPENDIX 139 INDEX 151 TOXICOLOGICAL MEMORANDA. INTRODUCTION. CHAPTER I. DEFINITION AND MODE OF ACTION OF POISONS. Toxicology (τοξικὸν poison, and λόγος discourse,) is that branch of medical science which treats of the nature, properties, and effects of poisons. It appears scarcely possible to give any definition of a poison which will bear a critical examination; insomuch that some have preferred to deal with the evil effects of any substance, that is _poisoning_, rather than with the substance itself, the so-called _poison_. Most medicines are poisonous in improper doses; and even common salt (chloride of sodium) has caused death.[A] Dr. Guy defines a poison to be any substance which, when applied to the body externally, or in any way introduced into the system, without acting mechanically, but by its own inherent qualities, is capable of destroying life. A cherrystone may cause death by becoming arrested in the vermiform appendix, and thus producing peritonitis; boiling water may cause death also; but neither are poisons: the one acting mechanically, the other by its heat merely.