The term âcarrier oilâ encompasses hundreds of different oils and butters. In the most basic sense, the word âcarrierâ serves to distinguish oils that are not âessentialâ oils. Common carrier oils include olive oil, coconut oil, shea butter, cocoa butter, grapeseed oil, canola oil, sweet almond oil, walnut oil, and more. The oils in this category vary wildly in terms of texture, colour, thickness, nutritional composition, and scent, but generally they are our base oils/butters.
In order to proceed with his research, Ebbinghaus had first to invent stimulus materials. These needed to be relatively simple, neutral as to meaning, and homogeneous. They needed to be available in large numbers and to allow quantitative manipulation of the amount of material to be retained.
William Withering, W. Bond, 19th century. Engraving of Carl Frederik von Breda painting. In 1785 William Withering, physician and botanist in Birmingham, England, wrote a book describing how for ten years he had used an extract of foxglove to treat patients afflicted swollen legs and abdomen.n the introduction to his book Withering described the variety of foxglove he used as digitalis purpurea, a flower commonly found and named digitalis in 1542 because its petals resemble the finger of a glove.