Royal Academy of Sciences of Paris. 167 



sensible alteration in the colour of the filaments ; and on the other 

 hand, that colour will frequently change by simple exposure to the 

 air, without any re-action being used. Mr. Coulier's method is by 

 far the best, but has the disadvantage, that all designs easily dis- 

 chargeable from the papers may become injured by time or acci- 

 dental circumstances, a consideration which, in cases of forgery, 

 would tend to render probable the impunity of the guilty by the 

 fear which would be entertained of condemning the innocent. The 

 use of these prepared papers must, therefore, be considered as very 

 secondary, the main security must be found in the indelible inks. 

 The discharge of the writing from old stamped documents, and the 

 consequent fraudulent use of the stamp, may be prevented, 1st. By 

 printing on all stamped paper, by means of a cylindrical press, 

 an engine-turned vignette, placed on the right of the stamp, in the 

 centre and along the whole length of each sheet. 2nd. By employ- 

 ing, in printing these vignettes, a colour having for its base the 

 black precipitate formed in the dyeing coppers of hatters, or ink 

 thickened in the manner adopted in the manufactories of painted 

 cloths ; and 3rd. By marking on all stamped papers the date of their 

 fabrication, either by printing it in the pulp, or engraving it on the 

 vignette or the stamp ; or, more simply still, by making the dry 

 stamp, impressed on each sheet of paper, revolve, so as to affix a 

 new date each year. This report was ordered to be transmitted to 

 the Minister of Justice. 



Gelatine. The discovery of Mr. D'Arcet, member of the Insti- 

 tute, of the means of preparing the gelatinous matter of bones, so as 

 to form a cheap and wholesome article of food, has excited great 

 attention in Paris. More than two years have elapsed since the dis- 

 covery, and the system of M. D'Arcet has been adopted in several of 

 the hospitals, and in the Maison de Refuge pour I Extinction de la 

 Mendicite of M. de Belleyme. The gelatine has also been used in 

 making sea-biscuits, which were used by the troops during the late 

 expedition against Algiers. The mode of preparing both the gela- 

 tine and the biscuits is minutely laid down in the pamphlets pub- 

 lished by M. D'Arcet. These experiments had invariably been at- 

 tended with success ; but on the 6th of June, M. Donne, a young 

 medical student, communicated to the Academy some remarks 

 tending to throw a doubt on the subject. He stated, that being 

 deeply impressed with the importance (particularly to the lower 

 classes) of ascertaining whether the gelatine did really possess the 

 nutritive qualities attributed to it by M. D'Arcet, he resolved to go 

 through a series of personal experiments on the subject. With this 

 view, recollecting that ten grammes of dry gelatine were stated to be 

 equivalent to half a litre (about two basins) of the best meat broth, 

 he began by taking that quantity every morning with three ounces 

 of bread, and gradually increased the quantity up to fifty grammes, 

 which constituted his sole nourishment up to six o'clock every day ; 



