Study of Spirogyra nitida. 



to preserve life for some time. Starch was not formed in 



the cells. 



(c) Green rays caused an active assimilation with a con- 

 tinuous growth and unusual protoplasmic motility. The 

 protoplasm was also in increased quantity. Green light 

 favored the production of crystals, particularly of calcium 



tartrate. 



(d) Yellow rays caused elongation of the cells, which 

 contained abnormal quantities of soluble carbohydrate, but 

 no starch, no tannin, and no crystals. The cells were 

 short-lived. 



(e) Orange rays caused a good growth closely approxi- 

 mating the normal. Crystals were not plentiful, however, 

 and the sugar was in rather large quantity. 



(/) Red rays caused a growth which was even more 

 rapid than that made in white light. Tannin was formed 

 in larger quantities than under the normal conditions. 



5. The action of monochromatic light, from the various 

 portions of the spectrum, upon solutions of diastase mixed 

 with starch paste, shows that yellow light causes the most 

 rapid hydration, while violet requires the longest period in 

 which to accomplish this result. The red rays required the 

 same length of time as white light. Wherever a marked 

 difference can be traced between the action of diastase in 

 rays of a certain refrangibility and in white light, there 

 too, the chemical composition and growth of Spirogyra is 

 abnormal; when, however, colored light and white light 

 coincide in their effect on diastase, the plant grows also. 



6. Spirogyra cells de-starch rapidly, and without decom- 

 position, if, while preserved in darkness, a stream of fresh 

 water or a current of air be supplied to them. Cells kept 

 in darkness, without an oxygen supply, show a solution of 

 the crystal content, and a general breaking down before 

 the starch has all been converted into sugar. 



7. Palladious chloride, in extremely dilute solution, serves 

 well to demonstrate the morphology of the nucleus and its 

 contents. 



