CHANGES DURING THE SPOILAGE OF TOMATOES. 11 



per cent). Hence, it was considered necessary to separate the lactic 

 acid by extraction with an immiscible solvent. 



The following experiments were made under the varying conditions 

 specified : 



(1) Used a 20 cc lactic acid solution which titrated 8 cc tenth- 

 normal sodium hydroxid. Saturated with salt and then added sul- 

 phuric acid ; extracted 5 tinies, using 20 cc of ether each time. Ex- 

 traction 50 per cent. 



(2) Saturated 25 cc of 1 per cent lactic acid with salt and extracted 

 as above; extraction 50 per cent. Similar solutions made strongly 

 acid with sulphuric or phosphoric acids gave practically the same 

 extraction. 



(3) Used 25 cc of 1 per cent lactic acid as in No. 2, but no salt or 

 acid; extraction 30 per cent. Using acetic ether in the same manner 

 instead of ether gave an extraction of 70 per cent. 



(4) Acidified 25 cc of lactic acid, 1.8 per cent, with sulphuric acid, 

 made up to 100 cc and extracted for 16 hours in the continuous extrac- 

 tor for liquids. Recovery from 98 to 100 per cent. 



(5) Added to 100 grams of good ketchup containing no lactic 

 acid 0.44 gram of lactic acid and treated as in the method given on 

 page 9. Recovery, 0.41 gram, 91 per cent. 



A number of special experiments have shown that when the extrac- 

 tion with ether is properly carried out no sugars will be found in the 

 extract, even when the solutions extracted contain a high percentage 

 of sugar. 



BEHAVIOR OF LACTIC ACID TOWARD OXIDIZING AGENTS. 



The following experiments were made to determine the behavior 

 of lactic acid under different conditions: 



(1) Ten cubic centimeters of lactic-acid solution, containing 0.12 

 gram of lactic acid, 8 grams of potassium hydroxid, and 40 cc of 

 potassium permanganate solution (8.4 cc = 0.5 gram of oxalic acid), 

 were heated on the steam bath for 30 minutes, and sulphuric acid 

 added to strong acid reaction. Fifteen cubic centimeters of 10 per 

 cent oxalic acid were then added and titrated with the permanganate 

 solution described on page 10, 2.2 cc being required. Found 0.119 

 gram instead of the 0.12 gram added. 



(2) Ten cubic centimeters of lactic-acid solution, containing 0.09 

 gram of lactic acid, oxidized with alkaline permanganate as described, 

 gave 0.127 gram of oxalic acid (H 2 C 2 O 4 + 2H 2 O) instead of the calcu- 

 lated 0.126 gram. 



(3) Ten cubic centimeters of lactic-acid solution, containing 0.221 

 gram of lactic acid with 8 grams of potassium hydroxid and 40 cc 

 of potassium permanganate solution (8.3 cc = 0.5 gram of oxalic acid), 

 was heated for 10 minutes on the steam bath, an excess of sulphuric 



