284 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



REICHERT'S METHOD, AS EMPLOYED IN THE DIVISION LABORATORY. 



About 2.5 grams of filtered fat are weighed into a rubber-stoppered 

 bottle, as in the previous methods, 25 cubic centimeters approxi- 

 mately seminomal alcoholic potash added, and the bottle heated on the 

 water bath until the fat is saponified. It is then rinsed with boiling 

 water into an evaporating dish and the alcohol evaporated. The resid- 

 ual mixture of soap and alkali is dissoved in 25 cubic centimeters 

 water, which is poured into a flask of about 200 cubic centimeters ca- 

 pacity, and the dish is rinsed out with another jDortion of 25 cubic cen- 

 timeters water, and this also added to the contents of the flask, 20 

 cubic centimeters of a 10 j^er cent, solution of phosphoric acid (specific 

 gravity 1.07) are added to separate the acid, the flask fitted to a con- 

 denser, and the volatile acids distilled off. When 50 cubic centime- 

 ters have distilled over, the process is stopped and the distillate 

 titrated with deci-normal soda. 



To prevent the liquid from carrying over non-volatile acid mechan- 

 ically, the tube which connects it with the condenser runs up straight 

 about 12 to IG centimeters above the flask before it bends, and is also 

 enlarged into a bulb, which is filled with broken glass or glass wool. 

 A coil of platinum wire is placed in the flask to prevent bamping, 

 andthe distillation is carried on at a sufficiently low temperature to 

 avoid violent ebullition. The total quantity of soluble acid in a pure 

 butter amounts to about 5 per cent. It may rise to 6 or sink to 4 per 

 cent, in some cases. 



_ In conclusion, I will say that with the aid of all the methods men- 

 tioned on the preceding pages the chemist is reasonably certain of 

 bein^Q^rable to distinguish a pure from an adulterated butter. 



Ic' appears further that the microscope with polarized light affords 

 one of the best means of qualitatively examining a butter for impu- 

 rities when the samples are fresh, while the estimation of the extent 

 to which an adulteration has been carried is best discovered by de- 

 termining the specific gravity and melting point of the fat, and by 

 subjecting it to the chemical processes just described. 



SIMPLE QUALITATIVE TEST FOR ARTIFICIAL BUTTER. 



The quantity of stearin in cow butter is small compared with that 

 in lard, tallow, &c. On this difference of constitution Professor 

 Scheffer (Pharm. Rundsch., 1886, 4, 248) has based a method of analy- 

 sis. A mixture is made containing forty volumes of rectified amyl 

 alcohol and sixty volumes of ether of . 725 specific gravity at 15° C. One 

 gram of butter fat is dissolved by 3 cubic centimeters of this mixture 

 at 26° to 28° C. On the other hand, 1 gram of lard required 16 cubic 

 centimeters of the solvent, 1 gram of tallow 50 cubic centimeters, 

 and 1 gram of stearin 350 cubic centimeters. 



For the experiment take a test tube of 12 cubic centimeters capacity 

 and place in it 1 gram fat, add 3 cubic centimeters of the fusel-oil 

 ether mixture. After tightly corking the tube put it in a water bath 

 at 18° C. and with frequent shaking bring the temperature to 28° C. 

 If the butter is pure the solution becomes perfectly clear at this tem- 

 perature. If not clear, more of the solution can be run in out of a 

 burette, and the additional quantity required will be some indication 

 of the quantity or quality of the adulterant which has been used. 



