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The latter substance corresponds to what is called an enzyme-substrate , but which 

 might better be denominated enzymoteel 1 ), the word enzyme-substrate being 

 evidently equivocal. To prepare a luciferase solution, free from luciferine, he leaves 

 the luminous mucus till it becomes dark. He makes a solution of luciferine, free from 

 luciferase, by slightly heating the mucus whereby the luciferase is destroyed. By 

 mixing the two dark solutions light is evolved, from which he concludes that the luci- 

 ferase acts as a catalysator similarly as other enzymes. The luminous slime consists 

 of the cell-content of peculiar glands of the epiderm and flows from the cell through 

 a fine canal ; it seems not impossible that it contains protoplasm. 



Various other sea animals as some Annelides, Cephalopodes and Coelenterates 

 likewise secrete a luminous slime, which spreading in the sea-water illumines the 

 surroundings of the animal. 



E. Newton Harvey has examined the phosphorescence of insects and comes 

 to the same results as Dubois, but he calls the related substances photogenine 

 and photopheleine 2 ). It is also easy to show that the phosphorescent cells of our 

 glow-worms, after mechanical destruction do not loose their luminosity. But these 

 facts cannot be considered as proving incontestably the accuracy of the enzyme theory, 

 it not being impossible that in all these cases not yet destroyed protoplasm is still 

 active. 



A better evidence for the view that the bearer of the phosphorescence consists 

 of one or more endoenzymes is to be derived from the luminous bacteria. Here the 

 production of light is inseparably bound to the bacterial body and secretion of a 

 luminous slime never occurs 3 ). If thus there is question here of an enzyme as cause 

 of the phosphorescence it can only be an endoenzyme, and that this supposition is in 

 accordance with the facts may be shown by exposing the luminous bacteria to the in- 

 fluence of ultra-violet light. It is namely possible by means of the light of a quartz- 

 kimp, to bring them into the necrobiotic state, wherein they have lost their power of 

 reproduction, but preserved their phosphorescence 4 ). If the time of the radiation is 

 well chosen, the necrobiotic condition may last for hours and it may be shown that the 

 luminosity of Ph. phosphoreum during this period is greatly intensified by glucose. 

 Hence the very same argument which leads us to consider the alcohol function of the 

 necrobiotic yeast-cell as an enzyme action, caused by one or more enzymes, called 

 zymase, holds likewise with regard to the connection between phosphorescence 

 and its factor or factors the luciferase. The still unknown luciferine which, as 

 said, can result in the case of Ph. phosphoreum from glucose, is the natural analogon 

 of the glucose-phosphoric-acid ester, i. e. the substrate or enzymoteel of the zymase. 



The necrobiotic yeast-cells have lost their semi-permeability, as shown by the ease 

 wherewith they are dyed by methylene-blue, their power of reproduction and cer- 

 tainly the motility of their protoplasm, whence they are considered as dead by several 

 investigators. The same is probably the case with the necrobiotic luminous bacteria; 

 but change of permeability could not be stated, since also in the condition of normal 



! ) Of telos, aim. 



*) Science N. S. T. 44, pag. 208, 440, 652, 1916. 



s ) The slimy matter produced by some kinds of luminous bacteria is non-phos- 

 phorescent cell-wall substance. 



4 ) For the particulars of this experiment see Folia microbiologica, Bd. 4, pag. 10, 1915. 



