FINAL DECISIVE EXPERIMENTS 277 

150° C., in which Bacteria, Micrococci, Streptococci, 
and large refractive Torule have been found, and 
when mounted and surrounded with paraffin, with 
all the care previously indicated (p. 246), all these 
organisms have multiplied beneath the cover glasses. 
Moreover, large numbers of Staphylococci have 
similarly multiplied beneath the cover glasses on 
two occasions—though never during the whole year 
have I once seen these latter organisms under any 
other conditions. 
Still, on other occasions, tubes containing sea- 
water that have been heated to such temperatures 
have remained barren. My experiments with this 
fluid have been limited in number and not sufficient 
to enable me to account for the very different results 
obtained on different occasions. I determined, there- 
fore, not to reproduce the photographs of organisms 
obtained from sea-water, and to limit myself in this 
work to an account of the remarkable results ob- 
tained with solutions containing sodium silicate as 
a principal ingredient. 
Before making some final statements concerning 
the major problem with which we have hitherto 
been concerned, a subordinate though highly in- 
teresting question in reference to these experiments, 
in which silicon has been present and carbon has 
been ostensibly more or less completely absent, must 
again be referred to. 
The question is whether we are to consider that 
silicon, whose chemical properties are so very closely 
allied to carbon, and, like carbon, first appears in 
