=The Nitrogenous Bases.=--The average nitrogen content of the pasty or solid extracts varies from 6 to 9 percent. The nitrogen in the meat juice is subject to much greater fluctuation, depending largely on the content of solids. Although a high nitrogen content is not a guarantee of the character or mode of manufacture of an extract, it is naturally expected and is desirable. The addition of gelatine to extracts is now largely practiced and has been for some years. By adding gelatine the manufacturer raises or maintains a certain nitrogen content, but supplies the nitrogen in a form lacking in all quickly stimulating qualities, and the natural flavor of the meat extract nitrogen is lowered. The buyer is consequently deprived of the characteristic essentials of a beef extract although the nitrogen content is relatively high. In many cases only a small proportion of the original gelatine exists in the extract as such. The gelatine is converted by a gradual process of hydration into gelatoses and gelatine peptones. While the separation of gelatine from protein matter is a process in anything but a satisfactory condition, it is a far simpler process than the detection and separation of gelatoses and gelatine peptones from albuminoses and peptones. The question has not been thoroughly studied up to date. The question of adulteration of meat extracts with gelatine is not the only form of adulteration we have to face. The mixing of varying amounts of yeast extract with meat extracts is being practiced at the present time in some countries. As we have not investigated this question, we cannot state whether it is practiced in this country at the present time or not. =Kinds of Preparations.=--Meat preparations of the above types in general may be divided into three classes, liquid extracts, pasty extracts and powdered extracts. In addition to the above, within the last few years beef extract pellets, some of them being enclosed in gelatine capsules, have appeared upon the market. The old-time product of Liebig’s extract belongs to the second class, in which we also find many of our best known brands. The liquid extracts are varied and numerous and their number is rapidly increasing. The amount of meat extractives in some of these liquid products is remarkably small, the quantity of solids in two or three cases being under 10 percent. Alcohol is sometimes met with in these liquid preparations. The meat powders are far less numerous than the extracts of the first two classes. They consist largely, if not entirely, of albuminoses and peptones in addition to some insoluble proteid matter.