some Marine Invertebrata. 21 



recognised. He explains the production of light in these animals 

 by the development of electricity from the surface of their bodies, 

 a development brought out by the action of the waves*. This 

 explanation is evidently untenable even in a merely physical 

 point of view. 



Lesson appears to us one of the first, if not the first, who has 

 seen in phosphorescence a phsenomenon distinct from the physico- 

 chemical actions which take place in our laboratories, but with- 

 out explaining himself very fully on this subject. This naturalist 

 regards phosphorescence as due to Crustacea belonging to dif- 

 ferent genera ; he allows that the seat of this light, emitted on 

 irritation or at the time of procreation, resides in glands placed 

 in a variable number on the sides of the thorax. He adds : — 

 " This light should be regarded as a fact established by investi- 

 gation, as a modification of the laws of life, and as different from 

 the simple sparkling light resulting from the decomposition of 

 animal substancesf." 



Carus, losing sight of the philosophy which prevails in his 

 works, adopts the opinion that this phfenoraenon is a property of 

 primary animal matter, which is nothing else than the nervous 

 substance, and which representing the solar element in the ani- 

 mal, necessarily appears luminous to the planetary element J. 

 He, then, as well as Oken, from whom he cites the passage, 

 "regards the jelly of Zoophytes, Medusas, &c., as the nervous 

 substance in its lowest stage, from which the other substances 

 embraced within it have not been isolated." 



M. Berard, cited by Duges§, regards the phosphorescence of 

 animals as due to a kind of luminous imbibition, or purely vital 

 effect, analogous to those which result in different bodies from 

 the action of heat, electricity, light, &c. 



Dr. Coldstream published in Todd's ' Encyclopsedia^ a very 

 interesting article on phosphorescence ||. After having examined 

 the natvu'e of animal light, the natural or artificial circumstances 

 which influence its appearance or intensity, the points of body in 

 different animals from which it is produced, he sums up all that 

 we have learned from different authors of the phosphorescent 

 organs, and the different theories proposed to explain these phse- 

 uomena. We quote from this English author some passages 

 from this part of his work. 



According to Beccaria, Meyen, &c., the phosphorescence of 



* Annales maritimes, 1817. 



t Diet, des Sc. Natur., 1826, article Phosphorescence. 

 X Traite elementaire d'Anatomie eomparee, traduit par Jourdan, t. i. 

 § Traite de Physiologic eomparee, t. ii. 



II The Cyclopaedia of Anatomy and Physiology, Part xxii. article Animal 

 Luminousness. 1841. 



