Qualitative Examination.

Protein.—As already mentioned, oysters contain a large amount of nucleo-protein or similar body rich in phosphorus. Besides this a saline extract of oysters contains a protein which coagulates about 75° C.

Fat and Pigment.—To the naked eye the ethereal extract of dried oysters appears brown, as is generally the case with fats dried at high temperatures. On spectroscopic examination this ethereal solution shows a distinct absorption band near the red end of the spectrum—apparently nearer that end than the characteristic band of methaemoglobin; on dilution the band approaches and fuses with the infra-red part of the spectrum. It is probably a lipochrome, as it is absent from watery extracts, and occurs only in extracts made by solvents of fat (ether, chloroform, acetone, alcohol, amyl alcohol, &c.). It was found in all the samples examined.