This subject can also be rendered apparent to the eye.  If we make a cross section of a grain of wheat, or rye, and place it under the microscope, we perceive very distinct layers in it as we examine from without inwards.  The outer of them belong to the husk of the fruit and seed, and are separated as bran, in grinding.  But the millstone does not separate so exactly as the eye may by means of the microscope, not even as accurately as the knife of the vegetable anatomist, and thus with the bran is removed also the whole outer layer of the cells of the nucleus, and even some of the subjacent layers.  Thus the anatomical investigations of one of these corn grains at once explains why bread is so much the less nutritious the more carefully the bran has been separated from the meal.[33] There can therefore be little doubt that the removal of the bran is a serious injury to the flour; and I have presented the above array of evidence on this point in the hope of directing public attention to it here, as has been done in various foreign countries.

After this, it will easily be inferred that I am not disposed to look with much favor upon the plan proposed by Mr. Bentz for taking the outer coating or bran from wheat and other grains previously to grinding.[34] Independently of the considerations which have already been presented, it is far from being proved, as this gentlemen asserts, that the mixture of the bran with the meal which results from the common mode of grinding is the chief cause of the souring of the flour in hot climates.  On the contrary, the bran is perhaps as little liable to undergo change as the fine flour, and then the moistening to which, as I am informed, the grain is subjected previously to the removal of the husk, is still further objectionable, and must be followed by a most carefully-conducted process of kiln-drying.

Nutritious properties of various articles of food.—­There seems to be some difference of opinion in regard to the nutritious properties of various kinds of food.  It is generally, however, agreed that those which contain the largest proportion of nitrogenous matters are the most nutritious.  It is on this account that haricots, peas, and beans, form, in some sort, substitutes for animal food.  Tubers, roots, and even the seeds of the cereal grasses, are but moderately nutritious.  If we see herbivorous animals fattening upon such articles, it is because, from their peculiar organisation, they can consume them in large quantities.  It is quite doubtful whether a man doing hard work could exist on bread exclusively.  The instances which are given of countries where rice and potatoes form the sole articles of food of the inhabitants, are believed to be incomplete.  Boussingault states that in Alsace, for example, the peasantry always associate their potato dish with a large quantity of sour or curdled milk; in Ireland with buttermilk.  “The Indians of the Upper Andes do not by