and this is sometimes regarded as an adulteration, but this is not the case; the potatoes assist the fermentation, and frequently potatoes cost more than flour.

Another addition to baker's bread is salt, which is sometimes added rather unsparingly.

By the aërated process bread is made without the introduction of yeast as a ferment, and carbonic acid gas is introduced in some other way. Now, there are two processes by which this is effected: first, by the decomposition of a carbonate; and, secondly, by the addition of carbonic acid. The first is the process by which the patent unfermented bread, recommended by Dr. Whiting, is produced; and the other is a process patented by Dr. Dauglish, and called aërated bread. Now, with regard to Dr. Whiting's process, it is very easy to understand. A little carbonate of soda is taken and put into the flour, then a quantity of hydrochloric acid is added to the water, and directly the hydrochloric acid comes in contact with the carbonate of soda, the carbonic acid is set free, and during the time the bread is being baked the carbonic acid gas is evolved, and common salt is formed. As hydrochloric acid is not always to be got pure, some persons recommend tartaric acid in its place. This forms tartrate of soda, which perhaps is not so desirable a compound as the hydrochlorate of soda or common salt. Bread thus made certainly keeps better than bread made with yeast. It is sold under the name of Dodson's unfermented bread.

The aërated bread is made by making the flour into dough with water containing carbonic acid gas in solution. This is done by using an apparatus like a soda

water machine, or gazogene, and injecting a quantity of water charged with carbonic acid into a cylinder containing the flour, and then the water is thoroughly mixed with the flour. This is done, by the aid of steam, m the course of a few minutes, and a valve in the cylinder is opened below and the dough is allowed to run out into little tin-cases, in which it is carried to the oven and baked. The carbonic acid is expelled during the baking, and thus the bread becomes vesiculated. The great advantage of this process is that, from the beginning to the end, you have no handling, no kneading, nor have you any of the waiting processes which beset the making of bread by fermentation. If you use German yeast and milk and warm water the bread will rise in three hours; if you use German yeast and no milk it will not rise under four hours; but frequently baker's bread stands nine, twelve, and even fourteen hours before it is put in the oven. This involves a great amount of human labour, and requires men to be sitting up all night. Thus it is that the baker's occupation is one exceedingly injurious to health; but by the aërated process the making of the dough is effected in the course of twenty or five-and-twenty minutes.

But the question as to whether the bread thus made is as good for health is one of great interest. It has been stated that man has eaten fermented bread from the beginning of the world, and that it is necessary he should do so, and that he instinctively prefers it, and therefore it must be best for health. Now this statement is not correct, for the great mass of mankind do not ferment bread, for they cannot ferment rice or maize. But we need not refer to Chinamen or Indians.

but to our Scotch neighbours, who, many of them, never eat wheat bread, but unfermented oatmeal, and there can be no doubt that they flourish on this diet. I think, therefore, this argument in favour of fermented bread must fall to the ground.

Then we may argue the matter as a question of taste. Well, if you like fermented bread best, there is an end of the question, and fermented bread has probably a sweeter flavour. During the fermenting process the starch has had a tendency given to it to change into glucose. In the aërated process there is no fermentation or change of the starch further than in the baking, and consequently fermented bread tastes sweeter in the mouth. The question is, is that an advantage? In some cases it is a disadvantage; as the fermented bread passes into a change further than glucose. There are many persons who cannot eat sugar, apples, pears, grapes, or anything containing glucose. They can eat a little cane-sugar, and that is all. Why? Because the stomach produces compounds which hasten the breaking up of the glucose and its conversion into acids. Thus it is that on some persons fermented bread acts as a poison. Many people can take dry toast who cannot take new or soft bread, and persons under these circumstances prefer biscuits that have not been fermented at all, and it is in these cases that unfermented aërated bread acts favourably.

I must, however, leave the question now with you to determine for yourselves. I will merely say that there is not that attention paid to the process of baking among bakers, and certainly not among people who bake at home, that there might be. The consequence

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is, that no two batches of bread are alike. Above all things, there is a necessity for attending to temperature during baking, and yet a thermometer, the only means by which temperature can be measured, is almost unknown among bakers. In Vienna, and many parts of Paris, they make much better bread, and a much more enjoyable bread, than any we have in London. This arises from the scientific attention given to the process. Here we carry on most of our occupations as if an entire ignorance of their nature were a means of

certain success. Is it then to be wondered at, that even in the manufacture of " our daily bread" we go to work in an expensive way, and produce an inferior and often injurious article?

Time will not permit me to speak of the other cereal grains, of barley, oats, maize, rye, and millet, containing gluten and albumen, nor of the leguminous seeds, peas, beans, and lentils, which all contain caseine; but I wish to mention the fact that other foods contain all the principles necessary to human subsistence. Thus there is the bread-fruit tree (Artocarpus incisa, Fig. 4), whose large fruits form a very delicious and substantial article of diet to the natives of the South Sea Islands. You may remember that the attempts in the last century to bring this fruit to England formed an interesting episode in the history of the voyages made to that part of the world. Most persons will have heard something of the voyage of Bligh to the Society Islands, and the mutiny on board his ship, and the escape of the mutineers to Pitcairn's Island, where their descendants are still located.

Another plant, belonging to a very different order, is the buckwheat. (Fagopyrum esculentum, Fig. 5.) It is cultivated in this country for the sake of its green fodder. But on the continent of Europe its ripe seeds are ground and mixed with wheat flour, and eaten as human food. The seeds contain nearly 9 per cent. of gluten, and 1 per cent. of fatty matter, 50 per cent. of starch, and 2 per cent. of sugar. In other parts of