174 



SCIENCE. 



[Vol. XVIII. No. 451 



SCIENCE: 



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ELECTRO-HORTICULTURE. 



In the winter of 1889-90 experiments were undertaken at the 

 Cornell University Experiment Station, by Professor L. H. Bailey, 

 to dotorminfi what influence the ordinary street electric light ex- 

 erts uyo- u'ciucc-. m gitjeui.^..^...^ " "las been said among gar- 

 deners c(m?etDing supposed retarding '■ • accelerating influences 

 of street lamps upo>' i^ilaats. Manyb.'.v- supposed that the elec- 

 tric light can be iiitroduced profitably into greenhouses for the 

 ' ' "";-o:fc of hssteuing growth. Still . "^hers have supposed the 

 lights at exhibition halls to be injurious to plants, and 

 r jid that f! 'vei- f?.;!'- 'jiiicToy vli placed near them. The 

 '. 1. .A .vahio.i : ght to vegetation should 

 be liiirJersToo:' 7 thought of introducing 

 ''■ V, "-' ■■■ ■ -r.^«iiaou-;«=. Jib iLinuei;:" jpou plants, both under 

 ■i in the open, i« a questio which demands careful 

 investigation. 



In recapitulating the results of the experiments made, Professor 

 Bailey says, in Bulletin 30 of the station, that it is impossible to draw 

 many definite conclusions from the researches made. The many con- 

 flicting and indefinite results indicate that the problems vary widely 

 under difl'erent conditions and with different plants. Yet there are 

 a few points which are clear: the electric light promotes assimila- 

 tion, it often hastens growth and maturity, it is capable of pro- 

 ducing natural flavors and colors in fruits, it often intensifies col- 

 ors of flowers and sometimes increases the production of flowers. 

 The experiments show that periods of darkness are not necessary 

 to the growth and development of plants. There is every reason, 

 therefore, to suppose that the electric light can be profitably used 

 in the growing of plants. It is only necessary to overcome the 

 difficulties, the chief of which are the injurious influences upon 

 plants near the light, the too rapid hastening of maturity in some 

 species, and, in short, the whole series of practical adjustments of 

 conditions to individual circumstances. Thus far, to he sure, 

 more of the injurious effects than of the beneficial ones have been 

 learned, but this only means that definite facts concerning the 

 whole influence of electric light upon vegetation are being ac- 

 quired; and in some cases the light has already been found to be 

 a useful adjunct to forcing establishments. 



The experiments suggest many physiological speculations, three 

 of which may be mentioned. It is a common notion that plants 



need rest at night, but this is not true, in the sense in which ani- 

 mals need rest. Plants have simply adapted themselves to the 

 conditions of alternating daylight and darkness, and during the 

 day they assimilate or make their food, and during the night, 

 when, perforce, assimilation must cease, they use the food in 

 growth. They simply practice an individual division of labor. 

 There is no inherent reason why plants cannot grow in full light, 

 and, in fact, it is well known that they do grow then, although 

 the greater part of growth is usually performed at night. If light 

 is continuous, they simply grow more or less continuously, as con- 

 ditions require, as they do in the long days of the arctic regions, 

 or as the plants experimented with did under continuous light. 

 There is no such thing as a plant becoming worn out or tired out 

 because of the stimulating influence of continuous light. 



It would seem, therefore, that if the electric light enables plants 

 to assimilate during the night, and does not interfere with growth, 

 it must produce plants of great size and marked precocity. But 

 there are other conditions, not yet understood, which must be 

 studied. The radish plants, and many others, were earlier but 

 smaller under the influence of the light. Observation and chemi- 

 cal examination showed that a greater degree of maturity had 

 been attained. Perhaps they assimilated too rapidly ; perhaps the 

 functions of the plant had been completed before it had had time 

 to make its accustomed growth. Perhaps the highly refrangible 

 and invisible rays from the electric lamp have something to do 

 with it. In fact, this latter presumption probably accounts for 

 much, if not all, of the injury resulting from the use of the naked 

 light, for the effect of the interposition of a clear pane of glass is 

 probably to absorb or obstruct these rays of high refrangibility. 

 Good results which follow the use of a globe or a pane of glass 

 show, on the other hand, that the injury to plants cannot result 

 from any gases arising from the lamp itself, as has been supposed 

 by some observers. In the experiments there was no perceptible 

 odor from the gases of combustion ; and it may also be said that 

 commercial forcing-houses are not tight enough to hold sufficient 

 quantities of these gases to injure plants. 



It is highly probable that there are certain times in the life of 

 the plant when the electric light will prove to be particularly 

 helpful. Many experiments show that injury follows its use at 

 that critical time when the plantlet is losing its support from the 

 seed and is beginning to shift for itself, and other experiments 

 show that good results follow its later use. 



HEALTH MATTERS. 

 Physiology of the Gastric Glands. 



According to Heidenheim, the delomorphous or parietal cells 

 of the gastric glands — that is, the glands of the fundus — secrete 

 or elaborate the hydrochloric acid of the gastric juice, while the 

 adelomorphous or central cells secrete the pepsin {British Med. 

 Jour.). One of the chief arguments advanced in favor of this 

 view rests on the experiments of Swiecicki, who asserted that in 

 the oesophageal glands of the frog pepsin alone is formed, while 

 only hydrochloric acid is formed in the stomach. Frankel has 

 submitted the statements of Swiecicki to a renewed test. He 

 prepared the mucous membrane of (1) the oesophagus, and (3) the 

 fundus of the stomach of ten frogs, and extracted each separately 

 in two litres of water. To eighteen centimetres of the watery ex- 

 tract of each there were added two centimetres of a one per cent 

 dilution of hydrochloric acid, and a small piece of fibrine. Both 

 mixtures were kept at 37° C. for twenty-four hours; both extracts 

 digested the fibrine. It would seem, therefore, that both the 

 oesophagus and stomach of the frog contain pepsin, or rather, 

 pepsinogen. This would tend to show that in the frog the delo- 

 morphous cells secrete both pepsin and acid, for fibrine is digested 

 in the stomach when the secretion from the oesophagus is pre- 

 vented from entering that organ. Frankel found that the mucous 

 membrane both of the stomach and oesophagus produced a min- 

 eral acid, for both gave the phloro-glucin-vanillin reaction. Con- 

 tejean finds that section of the vagi does not interfere with gastric 

 digestion in the frog. Electrical stimulation of the peripheral end 

 of the vagus, or of the central ends of the vagus or glosso-pharyn- 



