56 FOODS AND FOOD ADULTERANTS. 



Alien found that a genuine butter fat required not less than 12.5cc. * 



alkali for neutralization of the acid in distillate and that this corresponds 

 to 3.9 per cent, butyric acid distilled over, so that somewhat over 4 per 

 cent, of volatile acids in terms of butyric may be considered to be 

 yielded by the process. (Instead of 3.9 per cent, it should be 4.4 per 



N 

 cent, since Ice. caustic alkali neutralizes .0088 grams butyric acid.) 



Allen gives some comparative results with Reichert's method ob- 

 tained by different chemists. In the conclusion of the paper Reichert's 

 method is said to be more enlightening than Koettstorfer's for sorting 

 butters. 



Modification of Reiclierfs method by Dr. B. F. Davenport (communi- 

 cated in MSS.) Use only lOcc. of alcohol in the saponification ; the ad- 

 vantage being that with this small quantity the saponification is almost 

 immediate. In fact I begin to draw out the alcoholic vapor from the 

 flask as soon as it comes to the boil, using a water pump ; thus it takes 

 only about fifteen minutes to complete the saponification and the mass 

 evaporated down to a thick mass, free from any alcoholic vapors. My 

 process is to melt the butter at about 80 C.; filter off the clean fat, stir 

 it into a uniform mass as it solidifies. Weigh off two portions (for I 

 work in duplicate) of the solid mass of 5 grams each upon counterpoised 

 double filters of about the size of the scale pan, using double filters that 

 there may be no chance of anything going through to the scale pan- 

 Eoll up the edges of the double filter over the butter upon them, and 

 slip it all into an Erleumeyer flask. It is easy to get the ex act 5 grams 

 upon the open filter, and by putting all into the flask there can be no 

 loss in the transfer. Run off upon the butter in the flask lOcc. of 70 

 per cent, alcoholic solution, containing 2 grams of KOH. Saponify and 

 get dry mass in about fifteen minutes, add to it lOOcc. of water, dissolve, 

 aided by heat, add 50cc. of dilute H 2 SO 4 containing about one-tenth 

 part of commercial H 2 SO 4 , add several pieces of rough pomace loaded 

 with enough stout platinum wire to lie upon the bottom of the flask, 

 and then distill off lOOcc. directly into a sugar flask having a small 

 funnel, and filter in its mouth. 



I used at first after distilling off about 20cc. to pour it back into the 

 flask and then distill off lOOcc., but I soon learned that that made no 

 difference, as also using a 50cc. sugar flask full of diluted H 2 SO 4 , in- 

 stead of the directed 40cc., which was not quite so convenient a quantity 

 to measure off. I leave the end of the bulb tube connecting the flask 

 with the condenser long enough to enter the condenser so far that there 

 is no need of any rubber connection between them, there being no es. 

 caping at the upper end of the condenser of any v tpor or of scarcely 

 any odor at all. The operation requires no transferring of the material 

 from the beginning to end. Samples of known pure butter have by this 

 method required an average of 28.8cc. of alkali to neutralize the lOOcc. 



