94 THE DEATH-POINT OF 
most pertinent and valuable when considered in rela- 
tion to that supplied by other sets of experiments 
bearing upon the all-important problem of the Origin 
of Life. These latter experiments alone may possibly 
leave doubt in many minds; but the more thoroughly 
they are considered in relation to the evidence 
brought forward in this communication, the more 
fully, I venture to think, will every lingering doubt as 
to the proper conclusion to be arrived at be dispelled. 
Thus we now know that boiled turnip or hay-infu- 
sions exposed to ordinary air, exposed to filtered air, 
to calcined air, or shut off altogether from contact 
with air, are more or less prone to swarm with Bacteria 
and Vibriones in the course of from two to six days; 
but, placed under slightly different conditions such as 
were employed in the inoculation experiments above 
quoted, although infusions of the same nature do 
not undergo ‘spontaneous’ putrefactive changes, yet 
when living Bacteria and Vibriones are added, and 
not subsequently heated, putrefaction zzvariably takes 
place and the fluids thus situated rapidly become 
turbid, There is therefore nothing in the conditions 
themselves tending to hinder the process of putrefac- 
tion, so long as living units are there to initiate it, 
Our experiments now show that as long as the added 
Bacteria, Vibriones, and their supposed germs are 
subjected to a heat not exceeding 131°F. (55°C.), 
