Summary: THE Departmental Committee on Celluloid, appointed by the Home Secretary some fifteen months ago to consider the precautions necessary in the storage and use of this substance, has recently issued its report (Cd. 7158, 1913). From this it appears that the product accepted as “celluloid” in the report consists essentially of gelatinised nitrocellulose and camphor, the proportion of nitrocellulose usually varying from 70 to 75 per cent, in ordinary celluloid articles, and from 80 to 90 per cent, in kinematograph films. It ignites very readily, and burns with great rapidity and fierceness; moreover, in certain circumstances it may take fire without the direct application of flame. If submitted to a moderately high temperature for some time it suddenly decomposes with evolution of considerable heat and the emission of inflammable and poisonous gases—chiefly carbon monoxide and nitric oxide, with small proportions of hydrocyanic acid. Mixed with air in suitable quantity, the evolved fumes are highly explosive; but the Committee found no evidence to confirm the opinion that celluloid itself is liable to spontaneous ignition at ordinary temperatures or is explosive in ordinary circumstances.