be no more dispensed with in many instances than can the nourishing but easily digestible food, just alluded to, as the proper food for persons living under the artificial conditions of civilised life.

The chief ultimate elements forming the proximate principles of food are found in the body as under :

Chlorine, Sodium, Fluorine, Potassium, Iron, and Magnesium enter into the composition of several of the juices and tissues in different proportions.

In this diagram the identity of the components of food and the constituents of the body. are shown, and the mode in which chemical changes occur in organic as in inorganic chemistry may be seen. It may be well to give the shortest possible description of the processes of digestion and assimilation.

The mechanism employed in these processes consists in the organs concerned in mastication, insalivation, deglutition, the action of the stomach, duodenum, lacteals, and absorbents. The reagents which produce the chemical changes in the various kinds of food are contained in the saliva, the gastric fluids, bile, and the pancreatic fluid. The first of these owes its peculiar power of converting starch into sugar to the presence of an albuminoid compound called ptyalin. The solvent power of the gastric juice, which is specially directed to the breaking up of the nitrogenous matters such as meat, consists, again, of another albuminoid fermentative substance termed pepsin, which is only found in activity in conjunction with hydrochloric or other acids; these in themselves are secreted and brought out by the stomach during the process of digestion.

Supposing the digestion of those portions of the food, just alluded to, to have passed so far, the dissolved matter is poured out from the stomach into

the duodenum, or upper portion of the intestine, along with the other constituents of the food which have not been acted on by saliva or gastric juice. In this portion of the alimentary canal the mass of food which is called chyme receives the admixture of two most important fluids, the bile and the pancreatic juice.

The action of the bile is a distinctly antiseptic one, preventing the tendency to putrefaction and the development of the gases incident thereto. It also has the vitally important action of the preparation of fatty matters of food for their ultimate solution by the pancreatic fluid.

This is a matter which has been hitherto but little understood; but from some experiments which we have recently made, we have every reason to believe that the essential bearings of the subject will be better understood in the future, and that results will be obtained of such a character as will furnish the clue so long wanting for the successful treatment of those diseases in which emaciation is the most prominent symptom.

The food mass, or chyme, is by this time transformed into a milky fluid called chyle, mixed with those matters which have escaped the action of the process described. Such action continues to a greater or less extent upon these during their passage through the remainder of the intestines; but

the cellulose or woody fibre of the vegetables, and the harder or more fibrinous portion of the meat, and a large proportion of starch, still continues its onward progress, and is ultimately disposed of in an undigested form.

The absorption of matters in true solution takes place in the stomach, and these, such as the aqueous portion of soup, saccharine, and alcohol, are taken up by the stomach absorbents. But although this is very rapid with such solutions, the great work of selection and nutrition is accomplished after the food is passed into the intestines. Here, again, is a point, the consideration of which has been much neglected heretofore, viz., the carriers of the chyle, or lacteals, which suck up through the lining membrane of the small intestines, during their entire length, the real nutriment of the food as it passes over them, from thence to be distributed throughout the various tissues of the body; and each of which, in a condition of health, is replenished by a process termed assimilation, or the adding of those matters to themselves which are similar to their composition.

The mode of exemplification adopted at the lectures was very simple, namely, by samples in illustration of the various matters treated upon. Those selected were such as were most worthy of note in regard to their own peculiarities, or as types

of the different food values which may in a greater or less degree be found as components of simple or manufactured articles of food.

Some were purchased without the vendors being aware to what purposes they were being applied, some were supplied at the request of the lecturers, in consequence of their properties having been previously ascertained by personal examination, and some found their way to the lecture-hall without any notification from whence they came, or indeed of those who were good enough to send them.

None, however, were submitted as affording any exemplar of the subject touched upon, unless they had, either for the purpose of these lectures, or previously, been subjected to the most rigorous and searching analysis. From this it may be easily understood that many of the samples purchased, supplied, or volunteered, were not considered suitable for exemplification.

It is by no means one of the least pleasing experiences to be able to state emphatically, that in spite of the general disposition to depreciate, we have found to a much larger extent than we anticipated evidences of the attempt to bring forward pure, sound, and unadulterated articles of food, which only require a sufficient guarantee of a uniformity of their quality, and an extended pub