Hints and helps for home nursing and hygiene : a handbook for all who have to do with sickness arrange acording to the syllabus of the second (or nursing) course of lectures / by E. MacDowel Cosgrave.

  • Cosgrave, E. MacDowel (Ephraim MacDowel)
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: Hints and helps for home nursing and hygiene : a handbook for all who have to do with sickness arrange acording to the syllabus of the second (or nursing) course of lectures / by E. MacDowel Cosgrave. Source: Wellcome Collection.

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    It is by means of the diffusion of gases before men- tioned that the fresh air reaches the air-cells, and the foul gas in the air-cells escapes, to be discharged with expiration. Each breath taken draws fresh air some distance down the windpipe; here it meets the car- bonic acid, and changes places with it. The oxygen thus gradually diffuses its way down to the air-cells, and the carbonic acid gradually works its way out. The chest generally contains about 200 cubic inches of air; only 20 to 30 are breathed in or out in ordinary respiration, and this, because of its ebb and flow, is called tidal air. A double process thus goes on in the lungs. The air is taken in with plenty of fresh oxygen in it, and, is dis- charged foid with carbonic acid: the blood reaches the lungs laden with carbonic acid, and leaves it with a cargo of pure health-giving oxygen. DIGESTION. The two great ends achieved by digestion are, that it renders food soluble, and that it makes it capable of being absorbed into the blood-vessels. It is easy to imagine a gas passing through the wall of a capil- lary, but it is not so easy to think of fluid food soaking its way through living tissues, the wall of the stomach, for instance, and so into the blood. Fluid food does so pass, however, and the process by which it passes is called osmosis (“ forcing a passage ”). Osmosis is to fluids what “ diffusion ” is to gases (p. 24). If two ordinary fluids are separated by a moist membrane, they will gradually pass through the mem- brane and mix. The rate at which they will pass