536 



FOODS AND FOOD ADULTERANTS 



The last experiment (No. 5) was tried to ascertain the effect of washing the residue 

 with 30 instead of lOcc of absolute alcohol. The result clearly showed that much de- 

 pends on the amount of washing to which the residue may be subjected. This residue 

 is not absolutely insoluble in absolute alcohol, and it is probable that by excessive 

 washings it might all disappear. 



It does not appear from Professor Delafoutaine's testimony that he washed the 

 residue at all ; but, inasmuch as some of the liquid containing more or less of the dis- 

 solved material, would remain oil the filter, unless washed oft'by the alcohol, and dry- 

 ing, would improperly increase the weight of the precipitate, they deemed the wash- 

 ing with a very small quantity of alcohol necessary in order to arrive at true results. 

 He should not expect to get essentially different comparative results by not washing, 

 and as the whole experiment is comparative it makes little difference whether the 

 washing is done or not. 



Professor Delafontaine claims that the presence of tallow is proved by an increase 

 of the residue. The results of the experiments shown in the table prove exactly the 

 contrary, so far as they prove anything iu that respect. The admixture of cotton- 

 seed oil tends to greatly reduce the amount of the residue obtained by Professor Dela- 

 fontaine's method. 



CERTIFICATE OF W. M. HABERSHAW.* 



CHICAGO, July 5, 1863. 



I have analyzed three samples (sealed) of lard marked Nos. 1,2, and 3, delivered to 

 me by Dr. W. S. Haiues on the 21st of June, 1883, and find them free from adultera- 

 tion, and, in my opinion, pure lard. 



HABERSHAW. 



Mr. Habershaw said : t 



The analysis of fats has, until the last five years, been a question involving a great 

 deal of doubt. Among the first published methods of treating fats was the color test, 



Op. cit., p. 258. 



t Op. cit,, pp. 257, 258. 



