l82 MISCELLANEOUS EXPERIMENTS 



April 3, 8 A. M. 



There is no significant difference in the microscopic appearance 

 of the cells in the two cultures. 



The experiment was repeated with similar results. 



Experiment 59 

 Object : To ascertain the effect of the rays from radium on the 

 growth of the gemmae of Limularia. 



December 5, 2 P. M. 



A plant of Lumilaria was placed under a bell-jar in the dark- 

 room. Over the cupule, full of gemmae, was placed the sealed glass 

 tube containing 10 mg. of RaBr, of i ,500,000 activity, vertically, with 

 the end containing the radium at the height of the rim of the cupule. 



A control plant was similarly arranged, but with an empty glass 

 tube. 



December 8, 9 A. M. 



After an exposure of 67 hours, gemmae from the radiated cupule 

 were sown on the surface of moist sterilized soil, and a control sow- 

 ing was made from a plant not exposed. The cultures were placed 

 in the propagating house to develop. 



January 11. 



The radiated gemmae have never developed, while those not 

 exposed developed thalli of from 4 to 5 sq. mm. in area, and the 

 experiment was then discontinued, owing to an accident to the young 

 plants. 



Experiment 60 



Repetition of Experiment 59. 



January 17, 11 A. M. 



Gemmae of Lumilaria exposed for 48 hours to the rays from 

 RaBrg of 1,500,000 activity, were planted on the surface of soil in a 

 pot, and non-exposed gemmae were similarly sown in another pot. 



April 2. 



Both the radiated and control gemmae have developed thalli, but 

 those of the exposed culture are only about one half as large as those 

 of the control. The plants from the radiated gemmae began to de- 

 velop cupules about a month ago. These are now mature, with 



