DIURNAL PERIODICITY OF PHOSPHORESCENCE. 29 
Friday, October 2nd.—Vixamined at 3 p.m.; no phosphorescence, 
either spontaneous or on stirring. Hxamined again at 9 p.m.; in one of 
the Wednesday dishes there is an organism which remains permanently 
lit up the whole time of observation, about seven minutes. Spontaneous 
phosphorescence seen in the other Wednesday dish, and in one of the 
Thursday dishes. All four give phosphorescence on stirring. 
This is the second time a continuously phosphorescent organism has 
been observed. It may be a pathological condition of the organism. 
Saturday, October drd.— ixamined at 4 p.m., no phosphorescence of 
any kind; did not examine after nightfall this day. 
Sunday, October 4th—Hxamined at 12 noon, no phosphorescence in 
any dish, either spontaneously or after vigorous stirring. Jixamined 
again at 6-20 p.m., and watched at intervals till 8-30 p.m., but there is no 
spontaneous flashing. On stirring, however, there is phosphorescence 
obtainable in each of the four dishes, one or two organisms only flashing in 
each case. 
The experiments were brought to an end at this date. When the 
dishes are taken to the light it is found that only a small number of 
organisms are visible and alive in each, and there is much débris of dead 
organisms. 
The diurnal periodicity of the phosphorescence had been observed for 
twelve days and nights in the case of the organisms collected on 
Wednesday, September 25rd, and for eleven periods in the case of those 
collected on Thursday, September 24th, without any exception. During 
this interval, with the exception of one of the Wednesday dishes which had 
been exposed to light on the first Thursday of the period, all the dishes 
‘were kept in continuous darkness, yet at the close of the day the 
organisms always lit up, and lights were extinguished about daylight in 
the morning. 
The four dishes of organisms were now filtered one after the other into 
the small end of the same tow-net, washed out into a little sea-water, and 
fixed with five per cent. formol. 
The fixation was carried out in the dark room in order to observe if 
there was any phosphorescence. About six bright points shone out, two 
