SOLID PARTS OF ANIMALS. 



it is purer, and has a yellow colour. Various experiments on 

 this matter were made by the older chemists, showing it to be 

 analogous to animal fats,* and pointing out some of its peculia- 

 rities. Berzelius has examined it in detail, and published the re- 

 sults of his experiments.! The marrow on which his trials were 

 made was obtained from the thigh-bone of an ox. 



1. When marrow is digested in cold water it becomes lighter 

 coloured, while the water acquires the colour which it would have 

 received had it been digested on blood. When this water is 

 boiled it becomes muddy, and a dark-brown matter precipitates. 

 This matter consists of coagulated albumen mixed with some 

 phosphate of lime, and phosphate of iron. A small portion of a 

 yellow-coloured salt is dissolved by the action of alcohol or wa- 

 ter. This matter, separated from marrow by water, is obviously 

 owing to the blood with which it was mixed. The quantity which 

 Berzelius obtained from marrow amounted to iJ 5 th part of the 

 whole. The portion of it dissolved by water and alcohol con- 

 sisted partly of gelatin and common salt, and partly of the pe- 

 culiar brown extractive matter obtained by Thouvenel from the 

 muscles of animals, which will be described in a subsequent chap- 

 ter, when treating of the muscles. The proportion of these sub- 

 stances obtained by Berzelius from marrow amounted to about 

 j0th part of the whole. 



2. When marrow is boiled in water, the greatest part of it 

 melts and swims upon the surface of the liquid. The water is at 

 first muddy and milky, but becomes transparent on standing. 

 When passed through the filter, a substance is separated which 

 becomes greyish-green, and semitransparent when dry. More 

 of this matter precipitates when the liquid is evaporated. When 

 the water is evaporated to dryness, a substance is obtained of a 

 sharp aromatic taste like the marrow of roasted meat. These 

 two substances consist chiefly of extractive, gelatin, and a pecu- 

 liar substance, which approaches the nature of albumen in its 

 properties. 



3. When marrow, thus purified, is melted in water and passed 

 through a cloth, a quantity of blood-vessels and skins remain up- 

 on the cloth, amounting to about t J^th part of the whole. 



4. Marrow, thus freed from its impurities, has a white colour 

 with a shade of blue ; its taste is insipid and rather sweetish. It 



* Neumann's Chemistry, p. 560. f Gehlen's Jour. 2d series, ii. 287. 



