94 PHYSIOLOGICAL CONDITIONS AND FACTORS [CH. 



Potamogeton perfoliatus, P. pectinatus. In 2-3 % invert sugar there 

 was no result. In P. pusillus, a reddish colour appeared. 



In Najus major there was no effect but in N. minor there was a slight 

 result. 



Lemna minor, L. trisulca in various kinds of sugar solutions gave 

 negative results. The same was true for Pistia Stratiotes. 



Utricularia Bremii. In 2 % invert sugar reddening in the bladders 

 appeared in two to three days. Finally the leaves and bladders became 

 quite red. In 2 % cane sugar the result was similar. In Utricularia 

 minor, reddening appeared in -5 % cane sugar; also in glucose, invert 

 and cane sugars (-5 %-5 %). U. vulgaris behaved similarly to U. Bremii 

 and U. minor. In 2-5 % lactose, there was no colour in two weeks, 

 but after four weeks a slight colour (due to hydrolysis probably). 

 There was no colour in galactose; slight colour only in glycerine and 

 none in salt solutions. 



In Utricularia, reddening in sugar cultures developed just as little 

 in complete darkness as in Hydrocharis. 



Ceratophyllum demersum. In 2-3 % invert sugar there was some 

 reddening in the cells of subepidermal and deeper tissues, though the 

 epidermis was uncoloured. 



Experiments were next made with land plants, using either leafy 

 twigs or isolated leaves : 



Lilium Martagon. A leafy stem was placed in 2 % invert sugar. 

 This and control stems in distilled water were placed in a south-east 

 window. After about seven days, the plant in sugar solution showed 

 reddening in the leaf-tips, which afterwards spread, day by day, over 

 the leaf, while the control showed no reddening. The pigment was 

 found to be located in the inner leaf tissues, the upper and under epi- 

 dermal cells being free. Experiments were made with about 20 other 

 specimens, and in each case the results were the same. In 2 % glucose 

 solution reddening could be detected in four days, becoming more intense 

 in the course of time. In 2 % fructose, there was a similar result. In 

 2 % cane sugar the red coloration came later and was less intense. 

 In lactose, galactose and glycerine solutions there was no reddening, 

 and the same was the case with various salt solutions. It was found 

 also that ethyl and amyl alcohols, ketones and ether, in solution, caused 

 development of red pigment, but Overtoil considers the result to be one 

 of injury. He is inclined to believe that the alcohols, ketones, etc., 

 acted as narcotics and so prevented translocation, rather than that 

 they served as material for building up the pigment. 



