CHEMICAL CONSTITUENTS : ALBUMEN. 31 



Chemical Constitution of the Animal Body. 



13. By far the larger proportion of the Animal fabric is 

 formed at the expense of the substance termed Albumen; the 

 composition and properties of which, therefore, claim our 

 first attention. The fundamental importance of albumen in 

 the animal economy, is shown by the fact that it constitutes, 

 with fat, and a small proportion of certain mineral ingredients, 

 the whole of that mass of nutrient material stored up in the eggs 

 of oviparous animals, which, being appropriated by the germ 

 to the building up of its fabric, is converted by it into the 

 bones, muscles, nerves, tendons, ligaments, glands, mem- 

 branes, &c. of the embryo. "We find it also constituting a 

 large proportion of the solid matter of the blood and other 

 nutrient fluids of the adult animal ; and it is the fundamental 

 form to which the various azotized substances employed as 

 food ( 153) such as animal flesh, or the gluten of bread 

 are first reduced by the act of digestion. It is composed 

 of 49 carbon, 36 hydrogen, 14 oxygen, 6 nitrogen, with a 

 minute proportion of sulphur ; it is generally blended, also, 

 with more or less of fatty matter, and with saline and earthy 

 substances. 



14. Albumen may exist in two states, the soluble and 

 insoluble. In the animal fluids it exists in its soluble 

 form ; and is united (as an acid to its base) with about 1 

 per cent, of soda, forming an albuminate of soda. It is not 

 altered by being dried at a low temperature, but still retains 

 its power of being completely dissolved in water. "When a 

 considerable quantity of it exists in a fluid (as in the white of 

 the egg), it gives to it a glairy tenacious character ; but it is 

 nearly tasteless. "When such a fluid is exposed to a tempe- 

 rature of about 150, a coagulation or 'setting' takes place, as 

 in the familiar process of boiling an egg. But if the albumen 

 be present in smaller quantity, the fluid does not form a 

 consistent mass, but only becomes turbid ; and this only after 

 being boiled. Albumen which has been dried at a low 

 temperature, however, may be heated to the boiling point of 

 water, without passing into the insoluble condition ; a fact 

 which is of peculiar interest in relation to the power which 

 the Tardigrada (ZooL. 841) possess, of sustaining a very 

 high temperature without the loss of their vitality, when 



