most part identical with those in olive and palm oils, and in other animal fats; but the peculiar flavor of butter is due to the presence of 5 to 8 per cent of butyric, capric, caprylic, and caproic acids. These fatty acids are much less stable than oleic, palmitic, and stearic acids, which are often called the fixed fatty acids. In butter, human fat, and goose fat, palmitic acid is the most abundant. It is so named from its occurrence in palm oil. Oleic acid is common to these fats, and to beef, mutton, and hog fats. Stearic acid is found in small quantities in butter, while it is a chief and constant constituent of beef tallow.

During the Franco-German War, in 1870-71, a French chemist, Mége-Mouries, invented a process for obtaining from other animal fats the fatty acids common to them and to butter, and making from them a very fair artificial butter, for the use of the French army. The name oleomargarine is derived from the fatty acids present- oleic and margaric, as the mixture of stearic and palmitic acids was formerly called.

Oleomargarine and butterine are prepared in a similar manner from oleo oil (beef fat) or neutral lard and milk by churning and salting and coloring to imitate butter. These are wholesome food products, and their use furnishes a much needed fat to an economical diet. As a rule oleo keeps better than creamery butter, and if the latter is loaded with curd the oleo has a higher food value. But they should be sold under their own

names.

Rarely has there been a fraud so difficult to detect, since not only the apparent but the real

differences between genuine and artificial butter are but slight. Yet careful chemical analysis will show about 87 per cent of fixed fatty acids in butter, and about 95 per cent in the fats used in making artificial butter.

Reichert's process of determining the volatile acids peculiar to butter answers well in skilled hands. An analytical chemist has little difficulty in deciding upon the quality of a suspected sample. The expense attending such an examination, however, prevents its application as often as is desirable. The detection of the crystals of the different fats, as proposed by Taylor, may be an important aid. Some simple and easily applied test is much to be desired, but the public yet awaits its discovery.

Butter which has become rancid may be sweetened or "renovated" on a large scale by a process long used by the housewife in essential. It is melted, the curd and brine allowed to settle, and the scum removed; the butter fat is then aerated by a current of air blown through it in some cases to take out disagreeable odors, and then churned with milk, whole or skimmed, cooled, and packed. This butter will not keep as long as fresh, well-worked butter, and if sold without a correct label is a fraud.

The carrot and certain weeds served the farmer for his butter color. The dairies used annato, but the creameries find the coal tar yellows preferable. These may be detected by boiling bits of silk or wool in an alcoholic solution of the butter fat with the addition of water and cream of tartar.

One of the State chemists says, "The practice of coloring butter is now so firmly fixed, and the taste of consumers so bent to the false standard, that it is not probable that it will ever be abandoned."

CHEESE

Good cheese is composed of the total solids of milk curdled by rennet before the milk sours. Poor cheese is made from skimmed milk, and hence has less fat. Cheese is really a condensed milk, less the sugar and part of the mineral salts, and is a valuable article of diet, replacing meat, to a great extent, with those whose stomachs it suits; but on account of unjustifiable prejudice it is much neglected. One pound of dry cheese is estimated to contain as much nitrogenous substance as a pound or a pound and a half of beef as purchased. The rind of the cheese may have been brushed over with some metallic salt to preserve it from the attacks of fungi, etc, so that it is well to pare it off before eating.

The ripening of cheese has been the subject of much study.

The dairy schools give close attention to the production of all varieties, and very soon American cheese may be had of any desired quality, instead of the former crude, tough substance that is digested only with difficulty.

The great advantage of cheese is that it may be put up on the dairy farm under cleanly conditions and then transported and kept without change, being too concentrated for ready decomposition.

Dangerous preservatives rarely find their way into

cheeses. "Filled" cheese has the butter fat replaced by foreign fats, such as lard and cotton seed oil.

Eggs contain all the necessary constituents of food in the most concentrated form so concentrated as to be unsuited for the whole of the daily ration. For convalescents they are invaluable when they can be obtained fresh.

Eggs as bought consist of about 11 per cent shell, 32 per cent yolk, and 57 per cent egg-white or albumen. The yolk has the highest food value because it contains less water and more fat. Egg-white contains 86.2 per cent water, 12.3 per cent proteid, 0.2 per cent fat. Egg-yolk contains 49.5 per cent water, 15.7 per cent proteid, 33.3 per cent fat. The yolk contains more mineral matter and is an especially valuable food in anæmic and nervous conditions.

The egg production of the United States is one of 1 Table compiled by Woll, in Leach, p. 158.

the most important and valuable. It is estimated at not less than a billion dozens. Dietary studies have shown that eggs constitute three per cent of the total food.

The normal eggshell has a natural coating of mucilaginous matter which prevents the various microorganisms from passing through, at least for a time; but if this is washed or rubbed off putrefaction sets in and proceeds with rapidity because of the rich food material.

Water evaporates through the pores of the shell, so that old, unvarnished eggs are of greater specific gravity than new-laid.

Cold storage in a fairly moist atmosphere is the usual method of keeping and transporting eggs. They must be kept by themselves as they absorb odors very readily.

Various methods of preserving-packing in oatmeal or bran, covering with brine or lime water, treating with salicylic acid, varnishing with collodion or shellachave been tried, with a usual loss of half the pack.

At the North Dakota Experiment Station marked success has been obtained by coating the fresh, unwashed eggs with a dilute solution of water glass (one part of the thick, not too alkaline syrup as purchased to ten parts of water). These eggs are said to keep all their qualities, even that of beating up well for frosting.

Desiccated eggs have been successfully prepared for provisioning camps and expeditions. The water being removed enables four times the food value to be carried in the same weight.