The marshmallow is a confection that, in its modern form, typically consists of sugar or corn syrup, water, gelatin that has been softened in hot water, dextrose, flavourings, and sometimes colouring, whipped to a spongy consistency. Some marshmallow recipes call for eggs. This confection is the modern version of a medicinal confection made from Althaea officinalis, the marshmallow plant.
It seems likely that the marshmallow first came into being as a medicinal substance, since the mucilaginous extracts comes from the root of the marshmallow plant, Althaea officinalis, which were praised as a remedy for sore throats. Concoctions of other parts of the marshmallow plant had medical uses as well. The root has been used since Egyptian antiquity in a honey-sweetened confection useful in the treatment of sore throat. The later French version of the recipe, called pâte de guimauve (or "guimauve" for short), included an eggwhite meringue and was often flavored with rose water. Pâte de guimauve more closely resembles contemporary commercially available marshmallows, which no longer contain any actual marshmallow.
The use of marshmallow to make a candy dates back to ancient Egypt, where the recipe called for extracting sap from the plant and mixing it with nuts and honey. Another pre-modern recipe uses the pith of the marshmallow plant, rather than the sap. The stem was peeled back to reveal the soft and spongy pith, which was boiled in sugar syrup and dried to produce a soft, chewy confection. Candymakers in early 19th century France made the innovation of whipping up the marshmallow sap and sweetening it, to make a confection similar to modern marshmallow. The confection was made locally, however, by the owners of small candy stores. They would extract the sap from the mallow plant's root, and whip it themselves. The candy was very popular but its manufacture was labor-intensive. In the late 19th century, French manufacturers devised a way to get around this by using egg whites or gelatin, combined with modified corn starch, to create the chewy base. This avoided the laborious extraction process, but it did require industrial methods to combine the gelatin and corn starch in the right way. This treat became famously known in the civil war by colonal Gorge "Marshmallow" Pennigram, who loved this delicacy, and was ridiculed by former soldiers. 
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