Used principally as a garnish, or for making soup. Like lobsters in appearance, but smaller and of more delicate flavour.

Shrimps and Prawns can scarcely be classed as a food. They are best cooked in salt water, and have a distinctly appetising effect.

Mollusca are represented by the oyster, mussel, whelk, periwinkle, and cockle. The oyster is the most typical and popular, and is the only one described. Oysters are in season from September to April. There are several kinds; the "Natives" are considered the best.

The composition of oyster is mainly water, over 88 per cent.; proteid, 6 per cent.; and carbohydrates, 3 per cent. The proportion of solid nutriment is not large, three dozen moderate-sized oysters only containing 5 1/3 ounces of solids. The carbohydrate is present in oysters in the form of glycogen; this makes oysters unsuitable in diabetic cases where a rigid dietary is being enforced. When eaten raw, oysters are an exceedingly easily digested food, three medium-sized oysters being completely digested in three-quarters of an hour. Cooking tends to make them tough and leathery.

In recent years oysters have fallen into some disrepute, as they are known in some cases to have been the cause of typhoid fever. If oysters are grown in the mouths of rivers, they can easily be contaminated by typhoid germs in the sewage.

This risk can be avoided by keeping the oysters alive for a day or two in salt water which is frequently changed. This washes out and destroys the bacilli. Cooking renders them innocuous, but they are rendered less digestible by the process.

The roe of the sturgeon is known as caviare, when highly salted. It should be of a greyish colour when in good condition. Fresh roe of herring, haddock, and cod, prepared in different ways, are a very pleasant addition to an invalid's dietary, being both nutritious and easily digested.