﻿BOVIE— SCHUMANN RAYS 



When the dry spores of Monilia sp. are exposed to the light no 

 visible change is observed. If, however, after exposure the spores 

 are allowed to absorb water they become turgid, but their proto- 

 plasm assumes a coarsely granular, coagulated appearance, which is 

 quite different from the finely punctate appearance of turgid unex- 

 posed spores. When turgid spores of Monilia are exposed to the 

 light two kinds of changes are observed: either the protoplasm 

 takes on a coagulated appearance, after which no further change is 

 seen, or the spore wall suddenly bursts and some of the protoplasm 

 squirts out with such force that the spore is driven backward by the 

 reaction. The protoplasm, both outside and inside the spore wall, 

 appears granular. Approximately 50 per cent of the turgid spores 

 burst in this manner when exposed to the light. An exposure of 

 20 seconds, when the discharge tube is carrying 18 milliamperes, 

 is required to cause the spores to burst. A similar squirting out 

 of the protoplasm was observed in a Navicula-like diatom, and in 

 the spores of certain water molds when they were exposed to the 

 light. 



The fact that the light acts directly upon the organism itself, 

 and not indirectly through the formation of some toxic substance 

 in the medium, was made evident in the experiments in which the 

 drop containing the swarm spores was larger than the window of the 

 discharge tube, so that a few of the spores which were on the outer 

 edge of the drop were not exposed. Those swarm spores which 

 were not exposed to the light were not killed, even though they were 

 at the very edge of the illuminated area. When the exposure was 

 over they often swam into the region where spores had been killed 

 the instant before. As they entered this region they did not make 

 any change either in the rate or in the direction of their motion. 

 From this it may be concluded that the light did not produce any 

 toxic substance in the solution.* This conclusion is further strength- 

 ened by the fact that occasionally a swarm spore which was within 

 the range of the light from the discharge tube was protected from 

 the direct influence of the light by the shadow of some opaque 

 material contained within the drop. No change which could be 

 attributed to the action of the light was observed in such an indi- 

 vidual. Again, the fact that the position of the dead swarm spores 



