Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman.

  • Richards, Ellen H. (Ellen Henrietta), 1842-1911.
Date:
1900
Catalogue details

Licence: Public Domain Mark

Credit: Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    watery vapor given off (about 20 grams per person per hour) soon saturates the air, and the consequent drowsiness and headache usually attributed to carbon dioxide will be felt; while if this moisture is removed, the same proportion of carbon dioxide would hardly inconvenience the occupants. A relative humidity of 60 per cent, is said to be the most comfortable for house temperature. In normal man, exposure to cold increases the respiratory exchange; but if he represses shivering and keeps still by force of will, it apparently does not. Politely sitting still in- creases the probability of taking cold. A high temperature lessens the production of carbon dioxide and therefore saves food. This may in part account for the oppressiveness felt by well-fed and warmly clothed persons in public places none too warm for those with a more restricted diet. Muscular activity increases respiratory exchange and causes a demand for food. A class of students passing across the campus, up several flights of stairs, into a lecture-room vitiate the air for the first ten minutes at a rate higher by one part of carbon dioxide per 10,000 than half an hour later. The exchange is also stimulated by a meal. Not only the oxidation of the food itself, but the muscular activity of the alimentary canal and probably other accompanying activities call for an expenditure of energy which is supplied by in- creased heat production. Sodium sulphate is said to increase the various respira- tory activities, and some have held this fact to be one reason for the beneficial effects of certain mineral waters. The amount of carbon dioxide expired is estimated by Pettenkofer at .006 to .012 cubic foot per pound of body weight, according to the degree of exertion. Rubner con- siders that, in general, metabolic processes depend also upon the proportion of superficial area to the total volume of the