Spectral Colours on the Sporulation of Saccharomyces. 33 
17 February. 
9.45 a.m. Red light. Ellipsoideus shewed marked advance ; a certain 
number shewed perfect spores. Cerevisife had perfect 
spores in every cell. 
Green light. Ellipsoideus was very similar in appeai’ance as 
when examined at 10.45 p.m. (16 February). In Cerevisife 
the indications were apparently disappearing ; the cells 
appeared to be very thin and watery. 
Blue light. Ellipsoideus was unchanged, and the cells of 
Cerevisife were faint, thin and watery ; indications of 
sporulation were apparently disappearing. 
White light. Ellipsoideus was apparently the same as at 
10.45 p.m. (16 February); and in Cerevisife there were 
perfect spores in most cells. 
In the second series of experiments the gypsum blocks 
were seeded with very thin layers of pure cultures of Hansen’s 
S. Cerevisice I. and S. Pastorianus II., and in addition to the 
red, green and blue screens, a series of observations were taken 
with white light and a series in a covered box so that no light 
* could reach them. 
18 February. 
10.45 a.m. The blocks were seeded and left to incubate. 
19 February. 
9.30 a.m. Red light. Cerevisife shewed faint though certain indi- 
cations of sporulation ; and Pastorianus shewed very 
faintly. 
Green light. Cerevisife shewed very faint indications but 
not so advanced as in the red ; there were no indications 
in Pastorianus. 
Blue light. No indications in either Cerevisife or Pastorianus; 
the cells were very granulated. 
White light. In both Cerevisife and Pastorianus the appear- 
ance was exactly as in the red. 
No light. In Cerevisife, the appearance was like that in the 
green. Pastorianus shewed no indications except in one 
or two cells. 
2.15 p.m. Red light. Cerevisife shewed strong indications of sporu- 
lation ; as also did Pastorianus though not so markedly. 
Green light. Cerevisife shewed indications but not so 
strongly as in the red. Pastorianus shewed very faint 
indications. 
Blue light. In Cerevisife there were no indications of spores; 
in Pastorianus only a few cells shewed indications. 
White light. Cerevisife shewed indications though not so 
strongly as in the red ; whilst Pastorianus shewed very 
much like those in the red. 
VOL. XIV. 1>T. i. 
3 
