36 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN NO. 21 



minations were made in duplicate. The color of the supernatent 

 liquid after the precipitate had settled was used as a basis for esti- 

 mating the relative amounts of sugar present. A yellow liquid indi- 

 cated that there was more sugar present than was required to reduce 

 the Fehling's solution; a bluish color showed that the sugar which 

 was present was insufficient to reduce the Fehling. The following 

 simple experiment illustrates what has just been said. 



Several 5 cc. samples of an apple twig extract were taken as 

 follows: (1) Before dilution; (2) after diluting to twice its volume; 

 (3) to four times its volume; and (4) to eight times its volume. To 

 each of these samples 1 cc. of Fehling's was added. They were then 

 heated for several minutes. After cooling and settling, the liquid in 

 (1) was yellowish; in (2) a yellowish green; in (3) a bluish green; 

 and in (4) blue. The amount of precipitate was greatest in (1) 

 and least in (4). 



The color of the fresh extracts was another basis for estimating 

 the relative amounts of sugar contained in them. The apple twig 

 extract was generally light yellow to deep orange. By diluting the 

 deeper colored extract from two to twelve times with water, the 

 light color was obtained. Before dilution the deeper colored extract 

 showed more sugar than the light colored; after dilution, they con- 

 tained equal quatities of sugar. 



The results of these sugar tests substantiate those obtained 

 with the enzyme tests. The following determinations are typical, 

 and show the nature of the results. 



1. Jonathan apple twigs were collected September 23, 1913. 

 Some were etherized and some remained untreated. Sugar determi- 

 nations were made twenty-four hours after treatment. The same 

 experiment was repeated on October 28, and again January 12, 1914. 

 In the first case there was no noticeable difference in the amount 

 of readily soluble sugar of etherized and untreated twigs. A month 

 later, the treated twigs had more sugar than untreated ones. In the 

 last determination, both sets of twigs again showed similar amounts 

 of sugar. 



2. On December 7, 1913, one lot of Jonathan apple twigs were 

 immersed in 10 per cent alcohol for fifteen hours; a second lot was 

 dried at 35 C., fifteen hours; a third etherized twenty-four hours 

 and a fourth remained untreated. After twenty-four hours the 

 treated twigs showed the greater amount of sugar. On February 12, 

 1914, the same treatments were again applied to Jonathan twigs. 

 In this case the untreated twigs showed as much sugar as the treated. 



3. King David apple twigs were collected on February 8, 1914. 

 One lot was etherized for twenty-four hours, another bathed in 10 



