132 TESTIMONY OF ELWYN WALLER 



Q. In case it stood at 95 ? A. In case it stood at 95 if it were 

 commercial milk I should not consider it necessary. 



Cross-examined : 



Q. How long have you taught chemistry, Doctor ? A. Four or 

 five years. 



Q. Did you test the other evening a lactometer handed you by 

 Professor Doremus and myself? A. I did. 



Q. Did you find that to substantially agree with the Board of 

 Health lactometer ? A. Yes, it agreed essentially with the Board 

 of Health lactometer. 



Q. Did you test it at more than one point ? A. I tested it at 

 the same points at which I tested the other ones. 



Q. Did you test it so that you have no doubt as to its general 

 accuracy ? A. Yes, sir ; I did. 



Q. These samples of milk 86 of which you analyzed, did you 

 know them all to be pure ? A. Those that I tested in the country 

 you refer to ? 



Q. I think you said you analyzed 86 ? A. I analyzed 73 sam- 

 ples of milk ; I also tested 86 in the country. 



Q. The 73 that you analyzed, did you know them to be pure 

 milk ? A. I did not ; I knew that they were not. 



Q. How did you analyze those ? A. According to the ordinary 

 method ; I will describe the method if you wish ; the milk was 

 first dried to a constant weight ; then the butter fat was extracted 

 by means of ether, the loss of milk residue determined by the bal- 

 ance, and as a check upon that the amount of butter was placed in 

 a dish and the ethor evaporated off and that was also weighed ; 

 what remained consisted of caseine, sugar and salts ; the sugar was 

 then extracted by means of water and the loss noted and also the 

 weight of the sugar separated was determined ; the remainder con- 

 sisted of caseine together with some salts ; the sugar was burned 

 and the salts in the sugar thus determined ; the caseine was also 

 burned and the salts with the caseine was determined. 



Q. You are familiar with the general method pursued by the 

 Board of Health to detect the adulteration of milk in this city, are 

 you not ? A. I am. 



