394 ANNUAL REPORT SMITHSONIAN INSTITUTION, 193 8 



of Cypridina hilgendorfii. His results have been largely confirmed by 

 Kanda (1921 and 1924). Lucif erase exhibits definite protein prop- 

 erties, or, "if luciferase is not a protein it is so closely bound up with 

 a protein that it cannot be separated." Harvey estimated that 1 gm 

 of luciferase can accelerate the oxidation of 10,000 gms of luciferin 

 with the production of light. The fact that the activity of luciferase 

 is gradually diminished in the reaction does not prevent its being 

 classed among the organic catalysts (enzymes). Enzymes, in general, 

 are gradually used up in the reactions they generate and accelerate. 

 The chemical nature of luciferin is not as yet determined and Anderson 

 (1933, 1935, 1936) cannot agree with Kanda (1930) that it is a phos- 

 pholipid. Nearly complete precipitation by a saturated solution of 

 ammonium sulphate or phosphotungstic acid, insolubility in fat 

 solvents and hydrolysis by prolonged boiling with hydrolic acid, 

 indicate protein properties. On the other hand, solubility in con- 

 centrated alcohol and acetone, nondigestibility by proteolytic enzymes, 

 and the absence of a biuret reaction are not protein characteristics. 



(6) Distribution in organisms. — While luciferin has been ascribed 

 to various tissues of Cypridina hilgendorfii, luciferase is strictly 

 localized in the photogenic cells (Harvey, 1919). This is in contrast 

 to the phenomena of melanin formation in the elytra of Leptinotarsa 

 beetles, where the enzyme tyrosinase is distributed but the substrate 

 localized (Gortner, 1911). In earlier work, Harvey (1916a, 1917a) 

 believed that luciferin, but not luciferase, is also found in nonluminous 

 species of Cypridina. On the other hand, Kanda (1920) disagreed 

 with Harvey but agreed with Dubois by finding luciferin solely in the 

 photogenic cells of Cypridina and not in nonluminous species. Harvey 

 (1924a) later agreed with this view. 



(c) Evolution. — Bioluminescence is scattered throughout the animal 

 kingdom below the Amphibia but does not seem to carry any appar- 

 ent phylogenetic significance. As with regard to haemoglobin, 

 therefore, one would look for a certain basic substance present in 

 practically all aerobic cells which may be capable of giving rise to the 

 photogenic substances at random. Now, Harvey (1932) has pointed 

 out that fluorescent substances, such as practically all proteins, are 

 most likely to luminesce, and hence suggested that proteins with an 

 unusually bright "photophore" group are possibly seized in evolution 

 and made to luminesce by the energy of the oxidative dehydrogenation 

 of a luciferin. 



Is it merely a matter of chance that luminescence does not occur 

 among fresh-water forms? 



PHYSICAL PHENOMENA 



1. Efficiency in light production. — In the Philosophical Transactions 

 of the Royal Society of London for 1671, volume 1, page 603, is a brief 



