Only a few years ago, when Schutzenberger, emulator and forerunner of Fischer, Armand Gautier, Kossel, first disjointed the albuminoid molecule, to examine one by one its divers parts, the composition of the various albumins was very little known. Whether, therefore, albumins of the blood, or those of meat or eggs, were in question, these bodies were hardly ever separated, except through physical circumstances, amongst others by constant quantities of different coagulation. As to the centesimal formula and the intimate structure of the different protoid substances, they could be considered as closely brought together. From this fact, the physiological problem of the utilisation of albumin was simpler. No matter which article of food contained this albumin, its nutritive power by unity of weight remained the same. At the present time the number of albumins is no longer limited. It is not now physical characteristics founded difficult separations which arbitrarily distinguish those bodies from each other. The individuality of each of the albumins results from its formula of deterioration, under the influence of digestive ferments, or of chemical bodies acting in a similar way, as do mineral acids and alkalis. For want of constituary formula this methodical deterioration makes known the number of molecules (acids or other bodies) which are responsible for the structure of each albumin. These deleterious formula of proteid matter are not less suggestive than composition ones. They reveal notable differences between "vegetal" and animal albumins. To be sure, animal albumins (beef, veal, mutton, pork, etc.) which we are offered in an alimentary flesh diet, resemble more nearly the structure of our own bodily albumins than do the gluten of bread or the albumin of vegetables. This fact seems actually the best support of the theory which affirms the superiority of the flesh over the vegetable diet. Such a remark is therefore well worth discussing by showing that the consequences which can be deduced from it are paradoxical, and rest upon hypothesis which, not very acceptable in theory, are hardly verified in practice. Admitting that albumin plays in alimentary diet only the plastic part of reconstruction of used-up corporal matter, it might be advantageous to ingest but one albumin the composition of which is very similar to our own. By virtue of the law of least effort such a one in equal weights ought to be of more service than a foreign albumin, as it requires less organic work. For man, albumin of animal origin ought to be more profitable in equal weight than vegetable albumin. In the organism, indeed, albumin passes through a double labour. After the intestinal deterioration, followed by a passage through the digestive mucus membrane, a re-welding of the liberated acids takes place, with a formation of new albumin.