﻿i 9 i6] BOVIE— SCHUMANN RAYS 25 



are for the most part deposited on the surface of the gelatin, must 

 be used. 



Henri (19, 20) has shown that a very thin layer of egg white is 

 opaque to ultra-violet waves between 3000 and 2000 Angstrom units 

 in length, and that in this region the opacity increases as the wave 

 length decreases. If the absorption coefficient of egg white can be 

 applied to living protoplasm, and if the opacity of egg white con- 

 tinues to increase with decreasing wave length as we pass from the 

 region studied by Henri into the Schumann region, then it is reason- 

 able to suppose that the Schumann rays penetrated only a short dis- 

 tance into the substance of the organism. The extreme destructive 

 action of these rays is a result of the strong absorption. 



That the rays penetrate only a short distance into the substance 

 of the organism is indicated by the observations made on amoebae, 

 in which only a part of the protoplasm was killed by the exposure 

 to the light. It may have been that the nucleus and the protoplasm 

 which moved up into the vertical pseudopodium were well protected 

 from the shortest waves of the Schumann rays by the thick layer 

 of ectoplasm which remained below. Those parts of the proto- 

 plasm which were on the side away from the source of light were 

 killed by the longer, less active light waves only after a prolonged 

 exposure. Again, in the experiments on Spirogyra, the visible 

 changes always began on the side of the cell nearest the light. 

 Fungus spores, with brown or tan coloring matter in their cell walls, 

 even though the walls were thin, were not killed by a prolonged 

 exposure to the light. The Schumann rays could not pass through 

 the cell wall. 



Because of this strong absorption, the Schumann rays have a 

 marked localized action which gives them a peculiar value for inves- 

 tigations in the experimental morphology and physiology of the cell. 



In the experiments on the motile organisms, amoebae and infu- 

 soria, it was seen that the Schumann rays have a stimulating effect, 

 to which the amoebae respond by drawing in the pseudopodia and 

 assuming a spherical form, and to which the infusoria respond, first, 

 by an increase in the rate of motion followed by a decrease, then by 

 a loss of the power of coordination, and finally by the disintegration 

 of the riving substance. 



