ANIMAL SUBSTANCES. 141 



gulated albumen, an oil, or marrow, and phosphate 

 and carbonate of lime, besides other matters in 

 minute portions. 



Teeth are composed of similar ingredients. 



Shells contain a greater proportion of carbonate 

 of hme. 



Horns, nails, hoofs, and quills are chiefly gelatine 

 and albumen. 



Besides the animal substances above enumerated, 

 there are various matters secreted or formed by cer- 

 tain organs in the body, as saliva, the gastric juice, 

 the bile, thejluid ofi^erspiration, kc, the nature of 

 which is not yet thoroughly known. 



The examination of animal substances, called 

 animal chemistry, is one of the most difficult, as 

 well as one of the most important, branches of the 

 science ; and a wide field is yet open for research. 



When animal bodies are deprived of the vital 

 principle, and are exposed to the air, they undergo 

 a speedy decomposition called putrefaction. By 

 this they are resolved partly into their elementary 

 principles, and some of these form new compounds. 

 The first change is observed by the bodies altering 

 in their colour, losing their elasticity, and by their 

 giving out a very fetid and noxious sm.ell. The 

 greater part, in time, assumes a gaseous form, and 

 nothing remahis but a small quantity of earths and 

 salts. 



One of the greatest improvements in chemistry 

 has been that made in its nomenclature, which we 

 owe chiefly to the French chemists. As the former 

 names of many substances differ so entirely from 

 those at present employed, that, without some 

 assistance, many of the old writers on chemistry 

 are not now" intelligible to those acquainted only 

 with the modern nomenclature, a list is subjoined 



