August 11, 1916] 



SCIENCE 



209 



napthol, etc. It resembles the oxydones of 

 Batelli and Stern which are destroyed by ether, 

 chloroform and acetone. It passes with diffi- 

 culty through porcelain and is non-dialyzing. 

 At 60° C. it is destroyed by heat, as also by 

 digestion with trypsin. 



It is astonishing that work such as that re- 

 ferred to above, published in well-known jour- 

 nals by a competent physiologist, should have 

 received so little attention. No good account 

 of Dubois's work is to be found in any of the 

 physiologies in English or German, although 

 he is mentioned as the author of the luciferin- 

 luciferase " theory." I have recently been able 

 to confirm a great many of Dubois's statements 

 and to add some new facts. My material has 

 been the "West Indian cucullo, Pyrophorus, 1 

 the eastern American fire-flies, Photinus and 

 Photuris, and luminous bacteria. There is ab- 

 solutely no doubt of the existence of lucif- 

 erase and luciferin and the possibility of sep- 

 arating these two substances. 



I find that luminous bacteria also contain 

 luciferin in very small amount and this can 

 be precipitated by treating the bacteria with 

 absolute alcohol and drying quickly. Such a 

 dry powder gives no light with water, but a 

 faint light with the luciferase of the fire-fly. 

 I have been unable to obtain luciferase from 

 the bacteria, due probably to the fact that, like 

 so many of the bacterial enzymes, it is present 

 as an endoenzyme and can only be extracted 

 by high pressures. Curiously enough the bac- 

 terial luciferin can not be obtained by de- 

 stroying the luciferase through heat. Lack 

 of space does not permit of a discussion of 

 this here, but the full details will be published 

 later. 



Luciferase of one form will act with lucif- 

 erin of another, and vice versa. This is true 

 for the two genera of eastern fire-flies {Photi- 

 nus and Photuris) and for the West Indian 

 Pyrophorus (Elsteridce) and Photuris or Pho- 

 tinus (Lampyridm) . Fire-fly luciferin will 

 give no light with extracts of non-luminoua 

 parts of the fire-fly or with non-luminous in- 



1 My studies of Pyrophorus were made under 

 the auspices of the department of marine biology 

 of the Carnegie Institution of Washington. 



sects or extracts of pill bugs, earthworms or 

 slugs. 



Whether the luceferin and luciferase of all 

 forms are identical is still an open question. 

 We know of many organic substances such as 

 oils, alcohols, lophin, etc., which will phos- 

 phoresce at relatively low temperatures with 

 alkalies, so that it would be by no means re- 

 markable to find that the luciferin of different 

 forms was different. I have this past winter 

 discovered a luminous reaction which is re- 

 markable in many ways and which closely 

 parallels the method of light production in 

 luminous forms. Pyrogallol will produce light 

 with the vegetable oxidases (potato or turnip 

 juice) if we add some hydrogen peroxide. As 

 little as one part of pyrogallol in 254,000 parts 

 water (m/32,000) will give perceptible light 

 and m/8,000 a good light. Faint light is pro- 

 duced at 0° C. and a good light at 10° C. A 

 characteristic of luminous animals is that they 

 still produce light at 0° C. The pyrogallol -f- 

 H.O, corresponds to luciferin and the vege- 

 table oxidase to luciferase. Like the lucif- 

 erase of luminous forms the oxidase is de- 

 stroyed by boiling. We might therefore sep- 

 arate a luminous mixture of pyrogallol + H„0 2 

 and potato juice into a thermostabile and ther- 

 molabile component which would again give 

 light if brought together. Mammalian blood 

 may take the place of the oxidase of plant 

 juices. 



In a general way, then, we may say that the 

 problem of bioluminescence has been solved at 

 least in its broad aspects. There still remain 

 many details to be filled in, details which will 

 take some time to complete. The exact chem- 

 ical nature of luciferin is unknown, but the 

 method of attack of the problem has been out- 

 lined and all that is necessary is a sufficient 

 quantity of the luminescent material for the 

 determination of its chemical nature. That 

 it may be difficult to obtain enough for anal- 

 ysis is indicated by the luminescence of 

 pyrogallol which takes place in the almost in- 

 conceivably small concentration of 1 : 254,000. 



E. Newton Harvey 



Tokio, Japan, 

 May 1, 1916 



