Apparently, when behavioural scientists conduct salivation experiments using lemons, they hide the fruit. The reason for this, according to Margaret Visser in her impeccably researched book Much Depends on Dinner, is that subjects who see a lemon as well as taste one are liable to react in a manner that ruins the saliva measurements. Simply reading this had an enormous effect on my own saliva production, but I also tried to set up an experiment at home. My attempts, however, were sabotaged by family members showing me lemons, which did confirm something we already knew: perfectly packaged, handy in size, readily available, inexpensive, long-lasting and multitalented, lemons bring joy, even before you scratch or squeeze them.
While northern India, with its warm, humid climate that almost never gets colder than 10C, is where lemons very likely originated, Visser also notes that the first clear mention of lemons is, as far as we know, an Arab document from the early 10th century, in which the laimun tree is said to be sensitive to cold. Lemon cultivation in the Mediterranean was certainly the consequence of Arab initiative and the creation of orchards in north Africa, Spain and Sicily; it also seems likely that Arab traders sailed the lemons eastwards to China, where they met the bitter oranges and mandarins that originated in Assam and Myanmar. From China, citrus radiated to Malaysia, which seems to have been a producer of limes and pomelos. The very definition of fruitful encounters and exchange.
