<P> In the 19th century, smoking opium became common . Previously it had only been eaten, and then primarily for its medical properties . A massive increase in opium smoking in China was more or less directly instigated by the British trade deficit with Qing dynasty China . As a way to amend this problem, the British began exporting large amounts of opium grown in the Indian colonies . </P> <P> The social problems and the large net loss of currency led to several Chinese attempts to stop the imports, which eventually culminated in the First and Second Opium Wars . Opium smoking later spread with Chinese immigrants and spawned many infamous opium dens in China towns around South and Southeast Asia and Europe . </P> <P> In the latter half of the 19th century, opium smoking became popular in the artistic community in Europe, especially Paris in artists' neighborhoods such as Montparnasse and Montmartre being virtual opium capitals . While opium dens that catered primarily to emigrant Chinese continued to exist in China Towns around the world, the trend among the European artists largely abated after the outbreak of World War I . </P> <P> Ever since smoking was introduced outside of the Americas, there has been much vehement opposition to it . Arguments ranged from socio - economic, with tobacco called a usurper of good farm land--to purely moralistic, where many religiously devout individuals saw tobacco as another form of immoral intoxication . Many arguments were presented to the effect that smoking was harmful, and even if the critics were in the end right about many of their claims, the complaints were usually not based on scientific arguments, and if they were, these often relied on humorism and other pre-modern scientific methods . </P>

Who came up with the idea to smoke weed