76 On the Phosphorescence of Marine Invertebrata. 
Four tubes were filled with water containing the Noctiluce. 
Into one, oxygen was poured, into the second, hydrogen, the 
third, carbonic acid, the fourth, chlorine. The first three gases 
produced the same effect, and not more than atmospheric. alt 
occasions through the agitation its passage causes, After half an 
hour these tubes were shaken with precisely the same result in 
all. Chlorine acted like other irritating agents; the light was at 
first bright and continuous, but rapidly became extinguished. 
Macaire and Matteucci have shown that the light of the Lampytl 
is immediately brightened in oxygen, and rapidly extinguished by 
carbonic acid. The light therefore cannot be alike in origin 10 
the two cases. 
hos- 
phorescence, and in proportion to the intensity of the contractions. 
eat is conclusion was established by M. de Quatrefages by ex- 
periments upon the influence of pressure, heat and electricity ; of 
come away from the envelop, and collect about the mouth, leaving 
the envelop empty. In the dark, there is a very brilliant light at 
the first contact of the dilute acid with the Noctiluce ; then after- 
