---------------+---------------+--------------- |Genuine Butter.|Oleomargarine. ---------------+---------------+--------------- | per cent. | per cent. Water | 11·968 | 11·203 Solids | 88·032 | 88·797 +---------------+--------------- | 100·000 | 100·000 _Solids_: | | Insoluble fats | 75·256 | 81·191 Soluble fats | 7·432 | 1·823 Caseine | 0·182 | 0·621 Salt | 5·162 | 5·162 +---------------+--------------- | 88·032 | 88·797 ---------------+---------------+--------------- Lard is likewise occasionally used in the United States as an admixture to butter, the product, “lardine,” being sold either as oleomargarine-butter, or as the genuine article. Dr. Munsell mentions a factory in New York city where the weekly output of larded butter is 5000 pounds. As a result of the efforts of the New York State Dairy Commission, it has been estimated that the sale of imitation butter in this State in 1885 suffered a decrease of about 60 per cent., although the quantity manufactured in the United States showed an increase of 50 per cent. The specific gravity and melting point of butter have been suggested as criteria for its purity; in most cases, however, these determinations possess a rather limited value; as already stated, butter fat, at the temperature of 37°·7, has a density ranging from 0·91200 to 0·91400. The relation between the specific gravity of a fat and the proportion of insoluble acids contained was first noticed by Bell. This is shown in the following table which refers to pure butter fat. Specific Gravity | Per cent. at 37°·7. | Insoluble Acids 0·91382 | 87·47 0·91346 | 87·89 0·91337 | 87·98 0·91290 | 88·48 0·91286 | 88·52 0·91276 | 88·62 0·91258 | 88·80 0·91246 | 89·00 The following results have been obtained by the analysis of samples of various animal fats, and oleomargarine butter.