376 Profs. Percy Frankland aud Marshall Ward. 



In any case the death, cannot here be referred merely to the high 

 temperature, because, on the whole, the bichromate culture was at a 

 higher temperature than the other. 



On July 5 spores were sown in weak gelatine at 9 A.M., and 

 cultures kept in dark till 2 P.M. The sky was particularly blue, 

 but unfortunately I had to abandon the measurements at 4 25 P.M., 

 and on my return several hours later they had grown too long to 

 measure. 



So far as the measurements show there was no appreciable light- 

 effect up to 4 P.M., but after that the bichromate curve was making a 

 sharp rise out of all proportion to the temperatures ; it was unfor- 

 tunate that an engagement took me away from the observations just 

 at the critical p\rt, because the pursuit of this rise which ought 

 to have been les^ than the rise in the other curve, according to the 

 temperatures would have been interesting. 



But these cultures were placed next morning at 22. C. in the 

 dark incubator, and on the 7th July the one over bichromate had 

 formed excellent and normal chains of spores ; whereas the one over 

 water, though some spores were developed, was far behind in that 

 respect. So that, after all, there was an appreciable light effect in 

 the retardation of ppore formation. 



Spores were sown at 12 midnight on July 5, and kept at 22 in 

 dark incubator till 10 A.M. They were then exposed over a water 

 screen, quartz, as usual. The weak gelatine was used. The day was 

 very hot, and the haze in the early morning soon became thicker, and 

 by noon the sky was overcast; the afternoon was dull and intensely 

 sultry, ending in thunderstorms. From previous experience no light- 

 effect could be expected, and the following table and curve show that 

 no appreciable effect was obtained. The curve, on the other hand, 

 may be regarded as an almost perfect type of the growth record at 

 the temperature used, probably the optimum or a little beyond. 



The measurements could only be conducted directly on the whole 

 filament up to 5.3 P.M., but fortunately the filament then segmented 

 so distinctly into two parts, and at 5.30 into three parts, that, since 

 these remained iu contact and each quite straight but forming very 

 open angles one with another, I was able to measure each by itself 

 and add their growths. After 6.14, however, this became no longer 

 possible, partly owing to the enormously rapid growth and partly 

 to the lengths being greater than I could measure accurately. 



