Page:Popular Science Monthly Volume 29.djvu/76

66 on salivary digestion. This is wholly due to the acid—not the alcohol—they contain, and if this acid be neutralized, as it often is in practice, by mixing with the wine some effervescent alkaline water, this disturbing effect on salivary digestion is completely removed.

The influence of acids in retarding or arresting salivary digestion is further of importance in the dietetic use of pickles, vinegar, salads, and acid fruits.

In the case of vinegar it was found that 1 part in 5,000 sensibly retarded this process, a proportion of 1 in 1,000 rendered it very slow, and 1 in 500 arrested it completely; so that when acid salads are taken together with bread the effect of the acid is to prevent any salivary digestion of the bread, a matter of little moment to a person with a vigorous digestion, but to a feeble dyspeptic one of some importance.

There is a very wide-spread belief that drinking vinegar is an efficacious means of avoiding getting fat, and this popular belief would appear from these experimental observations to be well-founded. If the vinegar be taken at the same time as farinaceous food, it will greatly interfere with its digestion and assimilation.

As to malt liquors, provided they are sound and free from acidity, they interfere but little with salivary digestion; if they are acid, it is otherwise.

Effervescent table-waters, if they consist simply of pure water charged with carbonic acid, exercise a considerable retarding influence on salivary digestion; but if they also contain alkaline carbonates, as most of the table-waters of commerce do, the presence of the alkali quite removes this retarding effect.

"The use of these waters as an addition to wines is," Sir William Roberts observes, "highly commendable," as they "greatly mitigate or wholly obviate the retarding influence of these wines on the digestion of starch."

It was also observed that these weaker forms of alcoholic drinks (wines and beer) differed greatly in their influence on peptic digestion to that of the distilled spirits. They retarded it altogether out of proportion to the quantity of alcohol they contained. Port and sherry exercised a great retarding effect. "Even in the proportion of twenty per cent sherry trebled the time in which digestion was completed." It should further be borne in mind that this wine also greatly retards salivary digestion. Sherry, then, is not a suitable wine for persons of feeble digestive powers.

With hock, claret, and champagne it was also ascertained that their retarding effect on digestion was out of proportion to the alcohol contained in them; but champagne was found to have "a markedly less retarding effect than hock and claret"; indeed, in the proportion of ten per cent champagne had a distinct, though slight, accelerating