The character of the coagulation of the cheese originally has much to do with the general changes which the product undergoes during fermentation. The cheese makers for this reason must pay special attention to the rennet which they employ in the production of the precipitate. One of the most important of the changes which the casein undergoes is that which results in the production of ammonia. This indicates a complete decomposition of the protein substance, at least in part, so that the total amount of protein which is lost as such may reach as high as 25 or 30 percent of that present in the original cheese. There are also produced notable quantities of lucin and other nitrogenous compounds soluble in alcohol. In general it may be said that the changes in the nitrogen constituents of cheese are extremely helpful to digestion. Not only is the protein of ripened cheese more soluble but even the parts which remain unchanged as far as the protein constituent is concerned are so affected by the action of fermentation as to render them more readily subject to the action of the digestive ferments in the alimentary canal. There is a popular superstition that the use of cheese at the end of a meal helps to digest the other food which has given rise to the adage “Cheese, thou mighty elf, digesting all things but thyself.” There is a base of scientific truth in this expression since in ripe cheese the enzymes remain still in an active form and when taken into the stomach must necessarily exercise an influence of considerable magnitude upon the process of digestion. The custom, therefore, which is so universal, of finishing a dinner with a bit of cheese is evidently based upon sound physiological as well as gastronomical principles. _Changes in the Fat._--The chemical changes which the fat undergoes in the process of ripening the cheese are also of considerable importance. It is claimed by some authors that additional fat is produced from the casein during the process of ripening, which is the cause of the lardy appearance of some cheeses. Many observers have found in ripened cheese a larger percentage of fat than that which was noticed in the fresh cheese. This apparent increase, however, may be due to analytical error, since in the fresh cheese the fat becomes entangled with highly insoluble caseous matter and is difficult of extraction, whereas after the ripening of the cheese and degradation and breaking up of the caseous tissues the fat is much more readily extracted. While it is not impossible that fat should be formed by the fermentation of the casein it does not seem that it is probable.