TESTIMONY OF ROBERT OGDEN DOREMUS. 189 



teration of milk by water, for the reason that cream will lower the 

 lactometer as water does. 



Q. Is that the whole of the answer ? A. Yes, sir. 



Q. Now, sir, we have heard a great deal about the use of the 

 senses with the lactometer ; is it always customary for chemists, 

 when making any chemical tests, to use as many of the senses as 

 are available ? A. It is; we not only use the senses, but with the 

 eyesight we employ the microscope ; we employ the sense of sight 

 not only, but that of taste ; in all poison cases I invariably test by 

 the taste the contents of the stomach and the intestines ; we exam- 

 ine likewise by the sense of smell ; thus, as in prussic acid, one of 

 the tests is the peculiar characteristic odor of it. 



Q. Dr. Doremus, are there any variations of the simple methods 

 of testing milk ? A. There are, sir. 



Q. Will you explain them to the jury ? A. If in a little platinum 

 cup we place, say a dessert spoonful of milk, take its weight by an 

 accurate balance, having previously weighed the little platina dish, 

 warm it until all the water has evaporated, weigh it a second time, 

 and the loss is water ; pour on the residue some solvent for butter, 

 such as ether, allow it to stand a few minutes, pour off the ether 

 into a second weighed vessel, and repeat the treatment with ether 

 until all the butter has been removed ; you determine this by allow- 

 ing a drop of ether to fall on the surface of the glass and let it 

 evaporate ; there is a greasy stain, of course, and some of the 

 butter still remains ; dry the residue, weigh it, and the loss is butter. 

 We now know positively, your Honor, how much water and how 

 much butter were present. That which remains in the little dish is 

 the caseine or cheese, the milk-sugar and the salts ; for many pur- 

 poses this is all that is needed ; but if we heat the vessel containing 

 the residue red-hot, we burn up the cheese and the sugar ; now, we 

 weigh the residue the third time, and thus we have the salts ; know- 

 ing the weight of the water and the weight of the butter, the weight 

 of the salts, and subtracting these from the weight of the original 

 milk, we have the cheese and the sugar. If your Honor will per- 

 mit, I will make a little experiment. 



Mr. LAWRENCE We propose to show by taking a sample of milk, 

 not a quart, not a pint, but a tablespoonful, and subjecting it to a 

 total or partial analysis for the purpose of showing whether the 



