Hindu orthodoxy carries the belief in possible pollution by inferior auras to an extreme but logical extent. A high-caste person whose habits have not been changed by residence in the West or by contact with Western education will not allow a dog into his house as a pet or for protection. Its mere presence is regarded as unclean, so he will certainly never stroke it. And it is not only the propinquity of living creatures which may pollute him: even the handling of inanimate objects may do so if a lower-caste person has previously handled them. It is believed that such impure magnetism may remain attached for months.
-- Notebooks Category 15: The Orient > Chapter 2: India > # 251