622 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



that which is unquestionably of divine origin. But after the 

 animal ceases to live, then it forms a practical subject for inves- 

 tigation at the hands of the chemist. Then the chemist can 

 tell you what occasions the decay of the animal, and he can pre- 

 vent this decay, in a great measure. If it be a plant, if it be 

 wood, he knows that by the use of corrosive sublimate he can 

 coagulate the albumen in it, and prevent decay. 



Let us trace, for a few minutes, the chemical history of a dead 

 cow. I will not dwell upon the properties of the meat sold by 

 the butcher, nor upon other parts of obvious value, but will take 

 up those things which would seem to be mere offal. These are 

 all picked up, and nearly all of them can be converted into glue. 

 The bones are boiled to convert the fat into neatsfoot oil and 

 stearine. Of the latter, some is converted into candles, and 

 some, I am sorry to say, is used to adulterate butter. The small 

 pieces of skin are boiled down to make glue, a portion of which 

 is exposed to a certain degree of cold, and purified by chemical 

 means, rendered opaque and spongy, in which state it is called 

 gelatine ; for gelatine is merely frozen glue, prepared with special 

 care. At the bottom of the kettles, there will be a great deal 

 of hair and other sediment. That is not thrown away by any 

 means. The hair is used in the manufacture of brushes, or burnt 

 and mixed with other animal matter and sold as a manure. A por- 

 tion of the hoof is used for combs and similar articles. The 

 parings of the hoof are made into Prussian blue. The bones 

 are used for the handles of knives and forks, for buttons, 

 etc. The fragments of the bones are burnt into bone-black, 

 which is used in the sugar refinery; and after it has been 

 exhausted there, phosphorus is manufactured from it. Other 

 portions of the bones are treated with sulphuric acid, and con- 

 verted into a super-phosphate of lime, for manure. A portion of 

 the hoof is burnt into a form of carbon, used in the manufac- 

 ture of steel for taking impressions for bank notes. So that 

 a cow is, perhaps, even more useful after she is dead than when 

 she was living. 



Mr. Fisher inquired whether the refuse of bone or horn, used 

 to temper steel, should be thoroughly or partially carbonized. 



Mr. C. W. Smith. — The usefulness of sal ammoniac in case-hard- 

 ening, and of refuse bone in tempering steel, depends upon the 

 ammonia ; and hence we ought not to expel the ammonia before 

 using it. 



