8 



SCIENCE. 



[N. S. Vol. VII. No. 158. 



The portion of the conservatory employed 

 for the experiments was the north end of 

 one of the houses, where a bench space of 

 about 2m . X 3m. , and the height of the housej 

 was enclosed as a dark room, by hanging 

 black canton flannel and covering this on 

 the outside and on the roof of the house 

 with coarse cloths or board frames to ex- 

 clude the light. 



Experiment 1. Since in a number of cases 

 the use of the Kontgen ray for exploring in- 

 ternal parts of the human body has resulted 

 in certain injuries which are supposed to be 

 due to some action of the ray, the first of 

 the series of experiments which I conducted 

 with plants was for the purpose of ascer- 

 taining if there was any marked injury 

 which could be induced by an exposure of 

 about one hour's time. Indeed, those with 

 whom I discussed the matter prior to the 

 investigations, and who were familiar with 

 the use of the rays for other purposes, were 

 inclined to think that distinct injuries 

 would be produced. For the first experi- 

 ment a potted Caladium about 60 cm. high 

 was used. One leaf was supported directly 

 in front of the bulb and about 10 cm. dis- 

 tant, while a flat metal key was suspended 

 over the center of the leaf to intercept the 

 rays at this point. The light was turned 

 on at 11:07 a. m., June 6th, and a continu- 

 ous run was made of 1 hr. 18 mins., i. e., 

 until 12:25 p. m. There was no visible ef- 

 fect at the close of the exposure and subse- 

 quently the leaf remained to all appear- 

 ances normal. 



Experiment 2. For the next experiment 

 seedlings of corn, oats, German millet, sun- 

 flower and radish, which had been germi- 

 nated in small 2-inch pots a few days before 

 were used. The seedlings varied from 6 to 

 10 cm. in height. The pots were placed di- 

 rectly in front of the bulb, in such a man- 

 ner that each kind of seedling was situated 

 at different distances from the bulb in a 

 radiating row. The experiment started at 



1 p. m., June 6th. A piece of black canton 

 flannel was tied over the bulb to intercept 

 the electric light rays, so that their influ- 

 ence would not be felt, and this was kept 

 over the bulb during all the subsequent ex- 

 periments. At 2:45 p. m. it was noticed 

 that the plants nearest the bulb were so 

 close that electrical discharges took place 

 between the bulb and the leaves, causing 

 the plants to nod constantly toward the 

 bulb and even to come sometimes in con- 

 tact with it as the spark was formed. They 

 were then moved to a distance of 15-20 

 cm. At nearly 4 p. m. all the plants were 

 removed for a period of about three min- 

 utes while exposures were being made to 

 obtain photographs. With this exception 

 the seedlings were exposed to the influence 

 of the Kontgen ray for a period of ten hours, 

 the run being made from 1 p. m. to 11 p. m., 

 when the dynamos were shut down for the 

 night. No injurious effect was noticeable 

 nor could any be detected later. 



Experiment 3. The next experiment was 

 started at 6 p. m., on June 6th. For this 

 were used seedlings of corn, wheat, sun- 

 flower, radish, German millet and soja 

 bean. The seedlings were grown in a dark 

 room and were, therefore, etiolated, and 

 varied from 8 cm. to 20 cm. in height. The 

 plants were exposed that evening continu- 

 ously for five hours. The wheat, German 

 millet and corn seedlings were so frail that 

 they drooped in various directions. At 9 

 p. m. it was noticed that the seedlings of 

 the soja bean were turned slightly toward 

 the bulb, while at the beginning of the ex- 

 periment they were turned away from it. 

 Wo perceptible injury took place. 



Experiment 4. A potted begonia plant 

 was placed so that the delicate flowers 

 hung in front of the bulb within 10 cm. 

 and remained there for five hours. There 

 was no perceptible injury at the close of 

 the run; nor on any subsequent days could 

 injurious effects be observed. 



