Study of Spirogyra nit id a. 233 



By the close of the second day, provided the sunlight 

 continues, the chlorophyll hands are balled together more 

 or less tightly in the centre of the cell. This balling causes 

 the protoplasmic pellicle to recede from the cell wall, so 

 that it can be distinctly seen around the entire cell. When 

 such a cell is treated with a solution of iodine in potassium 

 iodide this pellicle takes on a violet-bine color. The fluid 

 in the cell-vacnole assumes the same tint, and the starch 

 grains, which are in considerable quantity, instead of show- 

 ing a pure deep blue, incline toward a violet. A test made 

 with Fehling's solution shows the presence of very little 

 sugar. The color which these cells yield with iodine, is 

 intermediate between the true starch blue and the violet of 

 erythrodextrine. 



These peculiar phenomena indicate that we are dealing 

 with a cell in which elaboration and metabolism are so re- 

 duced, at least in respect to starch transformation, that only 

 a very small proportion becomes soluble, and that little is 

 far from a true sugar. Judging from the coloration pro- 

 duced by iodine it is just beyond the amylodextrine stage. 

 This product does not seem to be utilized by the cell, nor, 

 so far as could be determined, is it carried to the sugar con- 

 dition. 



Ludwig Klein * has proved that the conidial stalks of 

 Botrytis cinerca do not grow during the day because of the 

 presence of blue-violet rays. A paper by Ward f on the 

 reduced growth of Bacillus anthracis in blue light, hints that 

 the reason may lie in some deep-seated chemical changes, 

 and the work of Macfarlanet on the sensitive plants, would 

 indicate that the chemical equilibrium of the cells is, for 

 the time being, much disturbed. 



The absorption spectrum of chlorophyll shows a dark 

 band in the violet: Hence, according to the theory of 

 Timiriazeff and his school, work is done by these rays. 

 Engelmann, too, reports an evolution of oxygen in the 



*Bot. Zeitung, 1885. f Proc. Roy. Soc, Vol. 53- 



JBotanisches Ceutralblatt, Vol. 61. 



