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THE POPULAR SCIENCE MONTHLY 



the electric light at night. Some plants, 

 which were taken into the conservatory a 

 few days before the electric apparatus was 

 put in operation, suffered badly from the 

 deficiency of light much more than the 

 experimenter had anticipated they would. 

 The plants that were constantly exposed to 

 the electric light became marked with spots, 

 and began in the course of eight days to 

 give evidence of having received serious in- 

 juries. That the spots were caused imme- 

 mediately by the light and not by the dis- 

 engagement of nitrous vapors, was shown 

 by the fact that only the leaves and parts 

 of leaves that were exposed directly to the 

 light were touched. This satisfied M. Dehe- 

 rain that the electric light contains rays 

 that are detrimental to plant-life ; and the 

 facts indicate that these rays are the violet 

 ones. A direct trial of the capacity of the 

 electric light to decompose carbonic acid 

 was made, with the result that less gas was 

 evolved from plants continuously exposed 

 within twelve feet of the light for several 

 days than is given out in an hour in the sun- 

 light. Plants that enjoyed the light of the 

 conservatory by day and received the elec- 

 tric light at night, suffered less, but were not 

 healthy. The electric light was inclosed in 

 globes of transparent glass and a new set 

 of experiments was instituted with new 

 plants. The mischievous effects of the vio- 

 let rays were no longer perceived, but the 

 light was not capable of maintaining a 

 healthy growth. The plants started well, 

 but sent out long, thin shoots, which with- 

 ered and died. Nothing but barley reached 

 a condition near maturity. None of the 

 plants would bloom ; but some of them 

 died at the top and took a new start from 

 the root to wither and die asrain. Con- 

 tinued experiments showed that these re- 

 sults were due to the lack of power in the 

 electric light to promote the activity of 

 evaporation required to bring the plants to 

 maturity. The plants that were kept in the 

 weakened, diffused light of the conservatory 

 by day, and in the dark at night, fell into a 

 gradual decay. Those that spent the day 

 in the shade out-of-doors, and the night 

 under the electric light, did better, but not 

 much better, than they would have done if 

 they had been left undisturbed out-of-doors. 

 M. Deherain concludes that the electric 



light has sufficient power to keep plants 

 alive that would die in the dark, and that 

 it exerts enough positive influence upon 

 vegetation to account for the seemingly 

 favorable results of M. Siemens's experi- 

 ments, in which vigorous plants that had 

 the light of day, and would have done well 

 anyhow, were made to do better by being 

 given also the electric light at night. 



Word-Blindness. M. Magnan, in a com- 

 munication to the Societe de Biologie, has 

 related two cases of aphasia complicated 

 with a special phenomenon, to which he has 

 given the name of word-blindness. One 

 case was that of a man who was seized with 

 a right hemiplegia and aphasia after a fall. 

 A month afterward, the patient recovered 

 the power of speech, little by little: he 

 understood spoken language ; he wrote, of 

 his own accord or from dictation, but was 

 incapable of reading either print or manu- 

 script, even when the latter had been written 

 by himself ; and he could not name letters 

 written upon a board. The second patient 

 presented similar symptoms. He recog- 

 nized objects which were shown him, but 

 could not name them ; could write words 

 thought or heard, but could not comprehend 

 what was written. He had lost the notion 

 of the value of gesticulations. A similar 

 case is reported by M. Brunardel, in which 

 a post-mortem examination revealed a dis- 

 ordered condition adjoining the pli courbe. 

 The pathology of the affection is explained 

 by supposing that the communications be- 

 tween the psychic visual center, which is 

 situated about the pli courbe, and the con- 

 volutions of Broca, are interrupted. In such 

 a case, the patient can still see, speak, and 

 hear, but can not acquire any new idea 

 through his eyes. " Brain " suggests that 

 since no disease of the eye exists, and the 

 affection is owing to a purely psychic phe- 

 nomenon, it might be better described as 

 " cerebral word-blindness." 



Death of Dr. J. B. Davis. Dr. Joseph 

 Barnard Davis, an eminent British author- 

 ity on skulls, died in May last, at about 

 eighty years of age. He made a voyage to 

 the Arctic regions as surgeon to a whaling- 

 ship in 1S20, while still a medical student, 

 then settled down in the potteries of Staf- 



