Spectral Colours on the Sporulation of Saccharomyces. 35 
4.30 p.m. Red liyht. Shewed about 50 °/ u or more of the cells with 
perfect spores. 
Green liyht. Most of the cells appeared to be becoming 
empty and no indications of sporulation in them ; 
although a few of them shewed strong indications and 
here and there there were perfect spores. 
Blue liyht. Most of the cells appeared very faint and empty 
looking ; although a few cells preserved the original 
very faint indications. 
White liyht. About 30 — 40 °/ n of the cells had perfect spores. 
No liyht. The spores were almost as well developed as in 
the red ; and more developed than in the white light. 
11p.m. Red liyht. The great majority of the cells had developed 
spores. 
Green liyht. Very like the appearance when examined at 
4.30 p.m. ; even the more perfect spores had a curious 
empty look. 
Blue light. No indications of sporulation were seen. 
White liyht. Hardly any change from and since 4.30 p.m. ; 
about 30 — 40 °/ 0 of the cells shewed perfect spores. 
No liyht. Strong sporulation observed exactly as in the 
red. 
21 February. 
10.30 a.m. Red light. Nearly every cell had sporulated. 
Green light. No increase in the sporulation, and those which 
had not sporulated wei’e becoming more and more empty 
looking. 
Blue light. The cells were apparently breaking down and 
becoming disintegrated. 
White liyht. No advance on the condition at 11 p.m. 
(20 February). 
No light. Nearly every cell had sporulated. 
The general results of the two preceding series of observations 
may be mentioned now, before proceeding to describe the remain- 
ing series. 
(1) The cells developed in the dark did not advance in 
sporulation quite so quickly as in the others at the commencement, 
but arrived at completion at about the same time. 
(2) The cells exposed to white light advanced at first more 
quickly than the cells in the dark, but not so quickly as 
in the red. The sporulation progressed up to a certain point 
and then stopped. An occasional dead cell, shown by staining, 
was noticed at the end of the experiment which was not noticed 
amongst the cells developed in the red and in the dark. 
(3) In the green light the cells apparently began to sporulate 
at the same time as those incubated in the dark. But the 
3—2 
