582 History of Luminescence 



ammonia, the surface of the body and of the gigantic tentacles shine 

 immediately with a brilliant azure light. The upper and lower edge of 

 the body are the parts where the light is most bright and abundant, so 

 much so that the outline of the animal can be perfectly seen. The light 

 is not communicated to liquids or solids put in contact with it, as hap- 

 pens in many other luminous animals. 



With a microscope Panceri noted that " the light escapes from 

 myriads of shining points which are more or less large and brilliant 

 and more abundant at the upper and lower edges of the animal." 



Squid and Octopi 



With the exception of Aristotle's mention of luminous squid (see 

 Chapter I) , one of the oldest records of a luminous cephalopod is 

 that of a polypus or octopus described by Oliger Jacobaeus or Jacobi 

 (1650-1701) , the distinguished physician and philosopher, professor 

 of medicine and natural philosophy in the University of Copenhagen. 

 He wrote in the Acta Medica et Philosophia Hajnensia for 1696 that 

 on opening the animal " it was so luminous as to startle several per- 

 sons who saw it; and he says that the more putrid the fish was, the 

 more luminous it grew. The nails also, and the fingers of the person 

 who touched it became luminous; and the black liquor which issued 

 from the animal, and which is its bile shown also; but with a very 

 faint light." ^^ From the description, a growth of saprophytic lumi- 

 nous bacteria on the dead octopus may safely be designated as the 

 source of the light. 



Many living squid are now known to have parasitic or symbiotic 

 bacteria associated with them. The light of these forms must have 

 been seen by many but descriptions are quite recent. Linnaeus does 

 not mention light from Sepia. W. T. Meyer (1906) investigated the 

 light in Sepiola, an allied species at Naples, but it was not until 

 1918 that U. Pierantoni pointed out the bacterial origin and held 

 that the bacteria of squid must be regarded as symbiotic. 



Many deep sea squid have lantern-like luminous organs on various 

 regions of the body. These peculiar skin structures had been ob- 

 served at the beginning of the nineteenth century but the first 

 knowledge of their luminosity appears to have come from observa- 

 tions of Jean Baptiste Verany on a large specimen of Histioteuthis 

 Bonelliana (see fig. 50) caught at Nice, France, in 1834. The 

 account of the animal is given in his Mollusqiies Mediterraneens 

 (1851) . He stated that the squid did not live long although placed 

 in a great bucket of sea water. Nevertheless, " during the night the 



*« From Priestley, 1772: 565. 



