English merchant William Methwold who visited India during the early seventeenth century says that he found certain castes who followed vegetarian diet, who had high standards of cleanliness practices he also found untouchable castes who ate beef freely, in contrast to the Hindu groups who regarded themselves as the people following higher standards by not eating beef which is considered a sin according to Hinduism since Hinduism forbids the eating of either cow or bull. British anthropologist John Henry Hutton traced the origin of untouchability to the taboo on accepting food cooked by a person from a different caste. This taboo presumably originated because of cleanliness concerns, and ultimately, led to other prejudices such as the taboo on marrying outside one's caste. Jaiswal argues that this theory cannot explain how various social groups were isolated as untouchable or accorded a social rank. Jaiswal also notes that several passages from the ancient Vedic texts indicate that there was no taboo against accepting food from people belonging to a different varna or tribe. For example, some Shrauta Sutras mandate that a performer of the Vishvajit sacrifice must live with the Nishadas (a tribe regarded as untouchable in later period) for three days, in their village, and eat their food.