222 ANNUAL OF SCIENTIFIC DISCOVERY. 



less proportion in muscle, and in a still less proportion in the stom- 

 ach. 3. In man, the quantity of phosphorus increases in a decided 

 manner, in proportion to his years, in the brain and in the muscular 

 flesh, and in a less marked manner in the stomach. 4. The less 

 quantity of phosphorus found in individuals under puberty, whose de- 

 velopment is not completed, arises from the greater quantity of this 

 metalloid required for the solid parts of the frame. 5. The difference 

 in the quantity found in an adult or a person of advanced age and an 

 individual under puberty, amounts, for the brain, to 1.14 compared to 

 1, and for the muscular substance to 2.19 as compared to 1. 6. The 

 amount of phosphorus found in the adult or aged person, and in the 

 ox, the caff, the sheep, and the hog (with the exception of the flesh 

 of this last), is very much the same, the average being, as regards 

 the brain, 1.560 in man, and 1.553 in the animals ; and as regards 

 the muscular substance, 0.872 in the former, and 0.876 in tire latter. 

 In the hog, however, the flesh contains 1.012, being rich in phos- 

 phorus, as compared with that of the other animals examined as 

 1.15 to 1. This may be one of the reasons why the flesh of this ani- 

 mal is more stimulating than that of others. 7. Flesh by boiling in 

 water loses one-half of its phosphorus ; so that the flesh of the hog, 

 which uncooked contains 1.012 per cent., after boiling only contains 

 0.567. Hence we see why in practice boiled meats are found to be 

 most suitable for the convalescence of those who have suffered from 

 hypersesthenic diseases, and why roasted meats impart vigor to those 

 whose strength has become exhausted by those of a debilitating char- 

 acter. The good effects of meats so cooked do not, however, solely 

 arise from the presence of a greater proportion of phosphoric com- 

 pounds. They also contain a larger quantity of the proper nutritive 

 principles of the flesh, which, being soluble in water, become lost in 

 boiling. Omodei's Annali Aniuersali. 



CLEANING AND PRESERVATION OF ENGRAVINGS. 



In a communication addressed to the Scientific American, Dr. A. 

 A. Hayes, of Boston, describes the following process for restoring val- 

 uable engravings which have become damaged through accident or 

 exposure. He says : 



In commencing to restore an engraving, some attention must be 

 given to the kind of injury it has suffered. A general brown color, 

 more or less deep, resulting from atmospheric action only, is the least 

 possible change. Spots and stains, caused by ink, colored fluids, oil, or 

 insects, must be first treated, and all pencil marks removed by India- 

 rubber or bread crumbs. A fluid acid, obtained by dissolving one 

 ounce of crystals of oxalic acid in one-fourth of a pint of warm 

 water, may be used for application to all stains, and the paper should 

 be wet with it thoroughly where spots of any kind exist. Excepting 

 in a few cases, this acid will not cause the removal of stains immedi- 

 ately, but generally it combines with the bases of them, and they are 

 removed by subsequent steps ; the thorough wetting should be done 

 a few hours before proceeding to clean the engraving. The engrav- 

 ing should then be placed in a shallow tub or other vessel, and 

 allowed to rest upon a piece of open cotton stuff, or inillinet. This 



