Poisonous Sherlock Holmes

Toxic- Detective = Sherlock Holmes

How Sherlock Holmes knew so much about poisons?

Before there was Sherlock Holmes and his trademark deer stalker cap, there was an English physician, Dr. Arthur Conan Doyle.

And before that there was just plain old Arthur Conan Doyle, a student at the University of Edinburgh Medical School, and where we will begin.
On September 20th, 1879 the British Medical Journal published a letter entitled “Gelseminum as a Poison” in which Doyle recounts his use of a tincture of gelseminum. Obviously prone to experimentation, the 19-year-old Doyle was “determined to ascertain how far one might go in taking the drug, and what the primary symptoms of an overdose might be.”
Allrighty then.
 Doyle prepared a fresh tincture and recorded his observations like any good scientist should. Pharmaceutical research is not unlike being a detective, you are constantly searching for clues and formulating explanations for whatever results might be generated.

Sherlock Holmes,and his drug-dabbling ways, did not make an appearance for another 8 years, but they are evident in Doyle’s exploits in self-poisoning and becoming a pharmaceutical detective.

Poison is an invisible murder weapon, which makes it appealing. Poison was used to seduce lovers, kill enemies and gain power; nothing was too noxious. Poison is seen as a "woman's weapon," and is typically administered by a femalehand. But the use of poison — featured prominently in several of most beloved plays — carried a special dramatic significance. 
Yet poisons—quiet, powerful, and sometimes secret- Drinking poisonous potion, poisoned wine and hit by a poisoned sword.

 There are a total of five cases of homicidal poisoning out of the 60 Sherlock stories, including in The Sword of Osman where a chief armourer is found dead following abdominal pain, dizziness and sweating. 

 Sherlock is able to immediately deduce that the man has died after being given Monkshood - a purple plant also known as the "Queen of all poisons".
Other plant references include that of opium in The Man with the Twisted Lip, and a deadly poison in The Adventure of the Devil's Foot.

 The mystery of how Sherlock Holmes knew so much about poisons has been cracked in the archives of the world-famous Royal Botanic Garden Edinburgh.
 Newly-unveiled records show the fictional detective's creator, Sir Arthur Conan Doyle, took a break from studying medicine to take a course in botany.
 Class rolls dating back to 1877 prove that a surprisingly green-fingered Doyle attended about 60 classes, seven demonstrations and nine excursions.
 The 140-year-old records bear the signature of a teenage Doyle, along with the the fact that he missed two classes through illness.
Doyle's studies went on to play a crucial part in the Sherlock novels as the legendary detective utilised his knowledge of poisonous plants to solve a range of murder mysteries.