94 HATCH EXPERIMENT STATION. [Jan. 



hours. The miicic acid has in the mean time crystallized 

 out, but is mixed with considerable material only partially 

 oxidized l)y the nitric acid. The solution is therefore filtered 

 through filter paper, washed with 30 c.c. of water, to remove 

 as much of the nitric acid as possible, and the filter and con- 

 tents brought back into the beaker. Thirty c.c. of ammo- 

 nium carbonate solution * are now added, and the beaker 

 brought into a water bath and heated gently for fifteen min- 

 utes. The ammonium earb )nate takes up the mucic acid, 

 forming the solul)le muciate of ammonia. The solution is 

 now filtered into a platinum or porcelain dish, and the 

 residue thoroughly washed with water to remove all of the 

 muciate of ammonia. The filtrate is then evaporated to 

 dryness over a water bath, and 5 c.c. of nitric acid of 1.15 

 specific gravity are added, thoroughly stirred and allowed to 

 stand for thirty minutes. The nitric acid decomposes the 

 ammonium muciate, precipitating the mucic acid, which is 

 now filtered onto a tared filter, or into a Gooch crucible, 

 washed with 10 to 15 c.c. of water, with 60 c.c. of alcohol 

 and quite a number of times with ether, dried at 100° C. for 

 a short time, and weighed. The mucic acid multiplied by 

 1.33 gives galactose, and this multiplied by .9 gives galactan. 

 The method gives fairly good results, but, like other 

 methods that are employed in estimating substances formed 

 by physiological processes, absolute accuracy is hardly to be 

 expected. For example, when extracting the mucic acid from 

 the impurities with ammonium carbonate, more or less of the 

 partially decomposed organic matter is dissolved out, which 

 is again precipitated by the addition of the nitric acid. After 

 the mucic acid is filtered and washed with alcohol and ether, 

 a considerable portion of this material is dissolved out ; some, 

 however, still remains, and gives the otherwise white mucic 

 acid a grayish color. It is possible that such a condition 

 might be obviated by previously treating the substance to be 

 examined with alcohol, ether and one per cent, soda solution 

 in the cold, in order to remove fat, coloring matter and pro- 

 tein substances. Whether this could be done without loss 

 of any of the substance is a question for further study. 



• One part ammonium carbonate, 19 parts water and 1 part strong ammonia. 



