Student's textbook of hygiene / [William James Wilson].

  • Wilson, William James.
Date:
[1915]
Catalogue details

Licence: Public Domain Mark

Credit: Student's textbook of hygiene / [William James Wilson]. Source: Wellcome Collection.

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    septicemia show a similarity to each other in their prevalence in years of sparse rainfall. A dry, warm soil with low level of sround water is an associated phenomenon in years when these diseases are unduly common. How the condition of the soil affects the incidence of these diseases is unknown, since there is no evidence for the theory that their specific contagia lead a saprophytic life in soil. (7) Goitre and Calculus have for many years been attributed to the consumption of water derived from limestone. Investi- gation, however, does not support the view that hardness of the water is a factor in the causation of calculus. Stone is frequent in India among people consuming soft water. Many authorities hold that Calculus must be considered as being due to a defect of metabolism resulting from an inherited idio- synerasy or from diet and mode of life. The recent work of McCarrison on the distribution of Goitre in Chitral, Gilgit, and Nagar has confirmed the view regarding the association of the disease with the drinking of water derived from limestone out- crops, and has thrown some light on the causative agent. (8) Lead-Poisoning due to the plumbo-solvent action of water derived from moorland areas has been frequently de- scribed, and one cause of the solution of the lead is the presence in the water of organic acids derived from the growth of certain acid-forming bacteria in peat. (9) Various parasitic worms are conveyed to man through the agency of soil. The ova of Ascaris lumbricoides and of Tenia echinococcus often reach water and vegetables from polluted soil, and the embryo of Ankylostoma duodenale can develop in moist soil if the temperature is sufficiently high, and can, when the soil is brought into contact with the epidermis of man, penetrate through the uninjured skin to the underlying capillaries and lymphatics; and it is probable that something similar happens in the case of infection with the Bualharzia hematobia.