Arsenic or cyanide?

One of the prized possessions on my mystery shelves is the Handbook for Poisoners (1951). The subtitle reads "A collection of great poison stories." And indeed it includes stories by great Golden Age mystery writers including Dorothy L. Sayers, E.C. Bentley, Agatha Christie, Anthony Berkeley, R. Austin Freeman, G.K. Chesterton, and earlier authors Nathaniel Hawthorne and Rudyard Kipling. It is a good selection of stories but the most valuable section of the book for mystery lovers is the seventy-five page introductory essay by the editor, "A Preface: About Poisons and Poisoning." From the flyleaf:

...[L]eading the reader into this treasury of malevolence, is Raymond Bond's introduction — as exhaustive as it is entertaining. With lively authority, he discusses not only the great poisoners of history, but also nature's own — the snakes, fishes, insects, trees, plants, etc. And to sum it up, he lists twenty poisons common to fact and fiction, with symptoms of each.

He begins with snakes:

...[A]ll poisonous snakes may be classified on the basis of their venom. Broadly speaking, their poison is either neurotoxic and attacks the nerve elements of the body, or it is hemotoxic or hemolytic and breaks down the blood and the tissue. In many instances, the same venom seems to contain both toxins to some degree.

Snake venom, when freshly drawn, is a colorless or slightly yellow liquid, without taste or smell; it quickly deteriorates unless it is dried, when it lasts almost indefinitely. It is not affected by cold but heat destroys it, as will certain chemicals such as nitrate of silver and potassium permanganate. The yellow crystals of the dried poison are soluble in a weak salt solution and generally in distilled water. Chemically, snake venom is a combination of proteids, too complex for analysis. It may be taken into the mouth and stomach without harm, provided there are no cuts or abrasions in the tissue walls. The neurotoxic type of venom destroys and paralyzes the nerve centers, such as those controlling the respiratory system; the larger the concentration of this element in the venom, the sooner death results. This is in the poison of the cobras and the coral snakes and makes them far more dangerous, other factors being equal, than the rattlesnakes. Indeed, it has been estimated that if a western diamondback rattler were equipped with neurotoxic venom, it would carry a sufficient quantity to kill four hundred men. The rattlers, copperheads and moccasins of this country, however, are dangerous enough with their own supply of hemotoxic or hemolytic venom. This poison acts on the blood and cell walls, breaking them down much as our digestive juices break up meat tissues. An antifibrin element prevents the blood from clotting and adds to the destruction. It is this escaped and blackening blood which produces the swelling and discoloration so typical of the pit-viper's wound. ....

And so on....  Then he lists those poisons most often used by mystery writers with a brief description of each. An example:

ARSENIC (or arsenium) — A steel-gray brittle metal, odorless and tasteless, and found with the other metallic minerals in the older rocks. In combination with sulphur, arsenic occurs naturally as realgar and orpiment. Arsenic and its soluble compounds are exceedingly poisonous, as mystery-story readers have learned. In its various forms, it is used in the production of green pigments, in glass and wallpaper manufacture, in dyes, in insecticides such as Paris green, flypapers, fruit sprays, and in rodent poisons. Arsenious oxide, sometimes called white arsenic, has an astringent sweetish taste and is white or porcelainlike in color. In addition to its popularity in commercial poisons, it is used in medicine for treating skin diseases, in malarial fevers, neuralgia and asthma. Limited amounts of arsenic have been used by women for many years in cosmetics and by men as a stimulant to increase their power of endurance. Symptoms of arsenic poisoning appear within an hour—a burning in the throat, stomach pains, cramps, pallor, shallow breathing, thready fast pulse, coma, convulsions and collapse.

I assume all of this sort of information is available from many other sources. If not this would be a rather disturbing "handbook." But for someone who reads Christie, or Sayers, or any number of others, or watches crime films or TV, it provides interesting background. Unfortunately the book is out of print, although both used hardbound and paperback editions can be found online at Amazon and elsewhere.