40 Lewis Knudson 



order of assimilability, although saccharose again appears to be the most 

 favorable. In all cases the amount of sugar utilized is greater than 

 the dry weight increase except in the maltose cultm^e. This is in keeping 

 with the results of J. Laurent (1904), and is explainable by the high rate 

 of respiration when the plant is provided with sugar (Palladine and 

 Komleff, 1902, and Maige and Nicolas, 1910). 



The plants grown in fructose, glucose, saccharose, and maltose were 

 easily distinguished from the check plants not only by a more vigorous 

 growi;h but also by the development of pigment throughout the entire 

 length of the stem. The color varied from pink to purplish, the fructose 

 culture showing a darker color than the others. Little color was produced 

 in the presence of lactose. The roots of the plants grown in the presence 

 of saccharose or fructose were in general thicker and showed a tendency 

 to cork formation. Li general the roots of all the sugar culture plants 

 except those grown in lactose were very much branched, while those of 

 the check plants were long and slender (Fig. 5). 



As in the preceding experiments, it was found that the saccharose of 

 the culture medium was partially inverted. The reducing sugar determined 

 in saccharose culture 1 was equivalent to 0.151 gram of glucose, while 

 that in saccharose culture 2 was equivalent to 0.125 gram. Approximately 

 one-fourth of the original sugar content was found inverted at the con- 

 clusion of the experiment. The check solutions did not give even a 

 qualitative test for reducing sugar, and no transformation of the lactose 

 or of the maltose was found to have occurred. 



A second experiment, similar to the preceding, was set up, the object 

 of which was a comparison of glucose and saccharose on the growth of 

 vetch in water cultures. Again the museum jars were used as culture 

 vessels, with perforated aluminum receptacles for supporting the plants. 

 The concentration of sugar emploj^ed was 1 per cent, and 50 cubic centi- 

 meters of the solution was used in each culture. The experiment was 

 begun on ]\Iarch 30, 1915, and concluded on April 24. Unfortunately 

 the comparison of glucose and saccharose is not conclusive, since in each 

 of the glucose cultures only one plant developed. However, if glucose 

 2 is compared -wdth saccharose 2 the advantage is in favor of saccharose. 

 The results are given in table 16: 



