PoDuted Waters

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Упражнение 10.Составьте письменно аннотацию текста А.

Упражнение И.Прочтите и переведите следующий текст; определите функции инфинитива.

The paper reports diarrhea in infants who drink water from local wells. These waters contained sulphate in a concentration of 600-1000 mg. per litre. The water was boiled before use, no microorganisms were found, and diarrhea could be induced or cured simply by manipulation of the sulphate concentration in the water. On the Canadian prairie many wells yield water which contains such a high concentration of minerals that it is too bitter to drink; water from other wells is palatable, yet many cause diarrhea. Sodium, magnesium and calcium were the

Lesson 21 О 213

most abundant cations to be present in these waters. Sodium always exceeded magnesium. The high sulphate concentration was sufficient by itself to account for the diarrhea. Sulphate is known to be absorbed and its purgative action can be explained entirely by its osmotic effect. The absorbability of the cation given with sulphate probably does not affect the purgative potcricy of the salt because sulphate retains an equivalent amount of cation during its passage through the gut. The purgative action of magnesium, another ion, which is poorly absorbed, could be similarly explained. Yet, magnesium is an ion of many parts and the possibility of a direct effect of a high concentration of magnesium on the motility of intestinal muscle cannot be discounted. Other, less scientific, observations have suggested that sulphate has the advantage over magnesium as a purgative.

Much remains to be learned about the transport and effects of these and other ions in the colon.

Часть II

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