124 THE DEATH-POINT OF BACTERIA 
of certain intrinsic peculiarities, when they undergo 
fermentation give rise to Zorule only. We are thus 
led to conclude that whilst some fluids are capable of 
engendering both kinds of organisms, others tend only 
to produce one or other of them—whether the fluids 
are contained in closed flasks or in open vessels ex- 
posed to the incidence of atmospheric particles. I 
have more than once seen nothing but Zorule appear 
in an infusion of turnip exposed to the air after it had 
been heated in a closed tube to a temperature of 293°F. 
for twenty minutes, and I have once seen the same 
thing occur in an unheated infusion of turnip exposed 
to the air, though on all other occasions such infusions 
have swarmed only with Bacteria and Vibriones. On 
the other hand, a boiled ammonic-tartrate solution ex- 
posed to the air, though protected from an excess of 
atmospheric particles (for the advent of a large number 
of these might in some cases incite putrefaction), is 
never found to contain Bacteria ; the fluid continues 
clear, though a sediment gradually accumulates at the 
bottom of the flask, amongst which Toru/g and other 
fungus-germs are constantly to be found—more nu- 
merous though otherwise very similar to those which 
are to be met with in flasks closed during ebullition, 
or in others to which only filtered air is admitted. 
Although Zorule only appear in such fluids, they 
continue all the time to be eminently inoculable by 
