204 CARNEGIE INSTITUTION OF WASHINGTON. 



Report on the Chemistry and Physiology of some Luminous Animals of Japan, 



by E. Newton Harvey. 



During a period of three months the author studied in detail four luminous 

 forms — a squid {Watasenia sdjitillans) , an ostracod crustacean {Cypridina 

 hilgendorfii), a pennatulid {Cavernularia haheri), and the Japanese fireflies 

 (Luciola parva and L. vitticolUs). The protozoon Nodiluca miliaris, unusually 

 abundant about Japan, was studied by Mrs. Harvey, especially as to light- 

 production and anesthesia. Observations were also made on the luminescence 

 of a fish (Monocentris japonica), the lantern squid {Inioteuthis inioteuthis) , 

 two hydroids {Sertularia sp. and Campanularia sp.), and Pennatula sp. Mono- 

 centris japonica is of interest because the light, which comes from two small 

 organs on the lower jaw, is steady and continuous, and not, as in most fishes, 

 a series of flashes, the result of stimulation. This fish, Pennatula, and the five 

 first-mentioned forms all give light if brought from daylight to darkness, a 

 condition quite different from that observed by Peters in the ctenophores. 



Watasenia sdntillans is caught in enormous numbers by the fishermen of 

 Toyama Bay on the northwest coast of Japan during April, May, and June. 

 The light from the tentacle organs is a brilliant bluish color, fully as intense 

 as that of the firefly; hence the Japanese name, "firefly squid" or "hotaru- 

 ika." The animal is a deep-sea forai which comes to the surface to breed; 

 it is consequently exceedingly sensitive and has proved to be of little value 

 for chemical research. 



Cavernularia haheri colonies contain a network of nerves connected with 

 the light-producing cells, and a brilliant wave of light passes over the colony 

 in every direction from the point stimulated. The light-wave will also pass 

 a cut completely isolating the surface epithelium and must be conducted by 

 inner tissues. The light comes from small granules in the fluid expressed by 

 pressure from the colony. This fluid glows for several hours spontaneously 

 and upon the addition of water will glow even after two days. The light 

 substance can not be preserved except by rapid drying, and in every way is 

 very unstable and quite different from that of Cypridina, described below. 

 The granules will not pass a Chamberlain porcelain filter. 



The light-substance of the firefly approaches Cypridina in properties, but 

 is more unstable and can be preserved for any length of time only in the dry 

 state. Space does not permit a discussion of the firefly apart from Cypridina. 



Cypridina hilgendorfii offers exceptional opportunities, as it contains a 

 large amount of luminous material giving a brilliant bluish light — a sub- 

 stance so powerful that it may be detected in at least a concentration of 

 one part in 1,600,000,000 parts of water. Could this material be synthe- 

 tized, there is no doubt of its efficiency for illuminating purposes. 



As first shown by Dubois in 1885 for Pyrophorus noctilucans and in 1886 

 for Pholas dactylus, there occur also in Cypridina two substances, separable 

 by heat, lucif erin and lucif erase (Dubois), which must be mixed, together with 

 water and oxygen, before light will appear. Each alone in solution is non- 

 luminous. This reaction is also given by the firefly (both Japanese and 

 American species), but not by Watasenia, Cavernularia, Pennatula, or Noc- 

 tiluca, despite the most favorable conditions. 



The evidence from Cypridina shows, however, that Dubois's theory of the 

 mechanism of light-production is incorrect. Luciferase, the thermolabile 

 substance, is the source of the light, and not luciferin, the thermostabile 

 substance, as Dubois supposed. The new names of photogenin (light pro- 

 ducer) for luciferase and photophelein (light assister) for luciferin have 

 therefore been proposed to indicate more truthfully the nature of light pro- 



