The following extract from the " Chemical Gazette," by J. Personne, will serve to throw some light on the question at issue between Dr. Montague and J. Downs, which was die-cussed in our columns, respecting the quick ferments employed for bread, c " The manufacturers of citric acid have long known the difficulty of keeping citrate of lime without its undergoing a change, but the nature of the products of this decomposition have hitherto been unknown. It was known merely that citrate ol lime, kept lor a certain length ol time, w ould no longer furnish'citric acid, and people were satisfied with saying that it was transformed into carbonic acid, or rather carbonate of lime. It is, however, difficult to rest upon this hypothesis, it we consider the formula of citric acid; the spontaneous decomposition of tartar, observed by MM. Noellner and Nickles, whilst augmenting the doubt as to our knowledge on this subjects serves also to attach a certain interest to the study of this decomposition. If, after saturating clarified lemon-juice with chalk, the paste of citrate of lime is put into a flask surmounted by a tube fitted for collecting gases, a disengagement of gas will be perceived in a day or two, when the operation is carried on at a temperature ol 86 to 95 Fak, and this continues until the trans- formation of the citrate is completed. When crude juice is employed in place of clarified, the decomposition proceeds more rapidly, a is shown by the more speedy appearance of the gases.