fruits are not dependent on the action of a direct sup- 

 ply of light for the formation of their pigment. In all 

 cases in which an interdependence betvreen exposure to 

 light and formation of pigment may be recognized, we may 

 venture to assvime that a specific action of light does not 

 ,lie at the root of the matter, but that nutritive con- 

 ditions, altered by the influence of the light represent 

 the decisive factors. Askenay (loc. cit.) observed that 

 shoots of Antirrhinum ma.ius and Digit alis pufpurpa. from 

 v.hich the leaves had been removed, developed white blos- 

 soms, clearly the result of a disturbance in nutrition 

 due to the loss of the leaves, Laurent (loc oit.) ob- 

 tained the sai:ie results by shading the leaves, while let- 

 ting the blossoms develop in the light. Unfortunately, 

 he did not name the plants with which he experimented. In 

 the case of Syringa the inflorescences, below which laurent 

 had girdled the branches, developed only pale blossoms, the 

 grapes from blue stock were incompletely colored if the 

 food supply was cut off by girdling. Coloration was en- 

 tirely absent if the grapes of girdled shoots were also 

 kept at the same time in the dark. Accordingly, it is 

 very probable that blossoms which, under normal nutritive 

 conditions, can develop their pigment only by exposure to 

 light, can become red or blue even in the dark, if in some 

 artificial way the necessary food stuff can be supplied 

 them in sufficient quantities. Doubtless, it will also be 

 possible to suppress the formation of red pigment in blos- 

 soms by unfavorable conditions of transpiration. 



Finally the influence of climatic pecularities on 

 the formation of pigment may also be explained by distur- 

 bances in nourishment. The reports that Petunia and Brach- 

 ycome in India-'- as well as Carduus nutan s in the neighbor- 

 hood of the sulphur baths of Pjatigorek TRuBSia)^ deserve 

 consideration and indeed, confirmation. For the present, 

 the factors are still unknown which cause the appearance 

 of so-called albinos in different plants,- individuals with 

 WMte bloosoTQS or fruits, instead cf those normally colored 

 red. The fact that many homogenous bacteria, under certain 

 (40) cultural conditions, temporarily lose the ability of pro- 

 ducing coloring matter, for instance . Micrococous prodig- 

 iosus at a high temperature (40 Degrees C.) may be men- 

 tioned in passing. With the bacteria v/hose formation of 

 pigment may be suppressed, the coloring matter is not 

 found in the cells themselves, but is excreted by them into 

 the surrounding medium. 



1. Gard. Chron, , 1881, 1, p. 627. 



a, Riesenkampf , Bemerkungen Uber einige in verschied- 

 enen Gegenden des russischen Eeiches vorkommende Anomalien 

 in der Form and Barbe der Gewachse, Bull. Soc. Imp. Matur. 

 Moscou, 1882, p. 85. 



