
FINAL DECISIVE EXPERIMENTS 269 
_ recorded in this Chapter, were purposely left exposed 
to light for a longer period, and subsequently placed 
in the incubator; because several other tubes con- 
taining such a solution, that had been similarly 
heated to 130 for 20’, on examination, after 
shorter periods of exposure, had been found to 
be barren. . 
These particular superheated tubes had been ex- 
amined earlier, because in the first experiment | 
performed this year with similar chemicals similarly 
heated (though in slightly different proportions), 
the result had been very successful. On opening 
this tube after seven and a half weeks and examin- 
ing some of the flakes of silica, plenty of Bacteria 
were found, and also a number of delicate Torule, 
both solitary and in groups, such as are shown in 
Fig. 28. Unfortunately I do not know the exact 
proportion of the different ingredients employed in 
this preliminary trial with such a solution heated 
to 130 C. for 20’, and subsequently exposed to light. 
But in no experiment since performed with an AA 
solution heated to such a temperature have I been 
able to obtain similarly successful results, as far as 
Bacteria and Torulz are concerned. 
I now have to refer to some remarkable experi- 
ments in which the BB solution, or a slight varia- 
tion of it, has been employed ; and in which longer 
periods of exposure to light and heat have been 
generally had recourse to. 
In the first two of these experiments to which I 
shall refer there were six rather than eight drops of 
