1281 
Phosphorescence considered as bound to protoplasm. 
Combination of the two views. 
That the function of phosphorescence of the luminous bacteria is 
bound to the living protoplasm is supported by the following facts. 
Anaesthetics, such as chloroform and aether, stop the light 
production almost completely, while after vaporisation. of these sub- 
stances it sets in anew, only slightly diminished. A short heating of 
temperatures near 40° to 45° C. of Ph. splendidum and of 30° to 
35° C. of Ph. phosphoreum, with subsequent cooling, has the same 
effect. By the action of acids and alcalies the phosphorescence 
disappears and returns after neutralisation. A strong salt concentra- 
tion darkens, after dilution the light is completely restored. 
Diminution of luminosity in these cases is caused by the dying of 
part of the germs. The phosphorescence of very active broth 
cultures, kept at rest for some time, undergoes a sudden and 
remarkable enhancement in its intensity by mechanical stimuli, such 
as shaking. The thus produced light reminds of the behaviour of 
higher luminous animals, possessing a nervous system, which by 
contact, or other mechanical stimuli, suddenly react with light 
production. 
All these facts induced me already long ago *) to call the bearer 
of the phosphorescence ‘‘photoplasm’” and its elementary units 
“nhotophores’. Also for the Flagellate Noctiluca miliaris px 
Quarreraces has demonstrated that the light issues from the proto- 
plasmic threads that run from the nucleus to the cell-wall which, 
when seen under the microscope, presents a large number of 
minute light centres, corresponding to the ends of the threads, 
closely grouped near the flagellum, but farther on the surface at 
greater relative distances. *) The sudden radiance of Noctiluca by 
shaking the sea-water wherein it is suspended is well-known. When 
“fatigued” the cells become entirely luminous and pr QUATREFAGES 
called the so produced light “pathological light’, but he does not 
say whether it originates from the cell-wall or the cavity. 
A principal argument for the view that the photoplasm of the 
luminous bacteria possesses the properties of the protoplasm lies in 
the relation between food and luminosity. For if peptones are 
present in sufficient quantity the phosphorescence is considerably 
1) De Ingenieur, 15e Jaarg. Pag. 53, 27 Januari 1900. 
2) Mémoire sur la phosphorescence de quelques invertebrés marins. Ann. d. sc. 
nat. Zoologie, 3me Sér. T. 14. Pag. 326, 1850. Vide also R. Dusors. Lecons de 
Physiologie générale, Pag. 498, Paris 1898. 
