Page:Popular Science Monthly Volume 24.djvu/796

776 economy of fuel is practiced in conducting it, and therefore less dissociation would be effected than in the domestic retail process.

Some of the early manufacturers of "bosch" purified their fat by the process recommended and practiced by the French Academicians MM. Dubrunfaut and Fua (see "Comptes Rendus," vol. lxxi) during the siege of Paris, when they and others read papers on the manufacture of "siege-butter" without the aid of the dairy. This consisted in frying the refuse fat from slaughter-houses until the membranous matter and other impurities were carbonized, and thus could be strained away. I wrote about it in 1871, and consequently received some samples of artificial butter thus made in the midlands. It was pure fat, perfectly wholesome, but, although colored to imitate butter, had the granular character of dripping. Since that time great progress has been made in this branch of industry. I have lately tasted samples of pure "bosch" or "oleomargarine" undistinguishable from churned cream or good butter, though offered for sale at 8d. per pound in wholesale packages. In the preparation of this I understand high temperatures are carefully avoided, and by this means the smoothness of pure butter is obtained. I mention this now merely in confirmation of my theory of the rationale of fat-cookery, but shall return to this subject of "bosch" or "butterine" again, as it has considerable intrinsic interest in reference to our food-supplies, and should be better understood than it is.

The cookery of milk is very simple, but by no means unimportant. That there is an appreciable difference between raw and boiled milk may be proved by taking equal quantities of each (the boiled sample having been allowed to cool down), adding them to equal quantities of the same infusion of coffee, then critically tasting the mixtures. The difference is sufficient to have long since established the practice among all skillful cooks of scrupulously using boiled milk for making café au lait. I have tried a similar experiment on tea, and find that in this case the cold milk is preferable. Why this should be, why boiled milk should be better for coffee and raw milk for tea, I can not tell. If any of my readers have not done so already, let them try similar experiments with condensed milk, and I have no doubt that the verdict of the majority will be that it is passable with coffee, but very objectionable in tea. This is milk that has been very much cooked.

The chief definable alteration effected by the boiling of milk is the coagulation of the small quantity of albumen which it contains. This rises as it becomes solidified, and forms a skin-like scum on the surface, which may be lifted with a spoon and eaten, as it is perfectly wholesome and very nutritious.

If all the milk that is poured into London every morning were to