PERSISTENCE OF PUTREFACTIVE AND INFECTIVE ORGANISMS. 
163 
On the 20th of November the infusions in all the chambers appeared to be as free 
from organisms as at first. The new Heathfield and the new London hay-infusions in their 
respective chambers had their somewhat turbid columns surmounted by an exceedingly 
clear zone of liquid, due, I should consider, to the mechanical subsidence of the particles, 
had not subsequent experience taught me to regard this appearance as a sign of life. 
On the 23rd scum had begun to gather on every tube of the case containing the 
infusion of old Heathfield hay. On the 30th this scum continued, but there was no 
trace of it in any of the chambers containing new Heathfield hay, new London hay, and 
old London hay. These infusions were all somewhat turbid ; but the turbidity differed 
very little from that exhibited when the infusions were prepared. 
I spent a good deal of time over these infusions of soaked hay, both with the micro- 
scope and otherwise, hut the recorded observations would not add materially to our 
knowledge. I therefore dismiss them with the remark that their general drift was in 
favour of the idea that the extraordinary resistance to sterilization manifested by the old- 
hay infusions is the result of hardening and desiccation. The foregoing observations, 
however, have been noted, more with the view of indicating my line of thought than of 
claiming for them any value whatever as a demonstration. 
§ 9. Infusions of Fungi. 
Turning from hay to substances in which germs, if they existed, could not be desiccated, 
I felt pretty sure that infusions of such substances would be unable to resist the boiling 
temperature. To test the correctness of this view the following experiments were 
made ' Three different kinds of fungi (red, black, and yellow) were gathered in Heath- 
field Park on the 13th of October, and digested separately in London on the following 
day. Three tubes of a closed chamber containing six tubes were charged with the red- 
fungus-infusion and three with the black, while a second chamber of three tubes was 
charged with the yellow-fungus infusion. They were all boiled for five minutes after 
their introduction into the chambers. 
For two or three days all the infusions continued clear; but, contrary to my expec- 
tation, they subsequently broke down, every tube of the nine becoming turbid with 
organisms and covered with scum. 
Examined microscopically on the 8th of November the red-fungus infusion was 
found charged with a multitude of spore-like bodies, massed in some places continuously 
together, in others floating freely in the liquid. Among these ran long filaments, dotted 
with spore-like specks from beginning to end. There was a considerable number of 
Vibrios in one of the tubes. The black-fungus infusion contained a mixed population 
of Vibrios and Bacteria with spore-filled filaments. Swarms of Bacteria were observed 
in the red-fungus infusion. 
Suspicious of the chambers in which these infusions had been exposed, I had three 
new ones constructed and provided with new tubes. A fresh supply of fungi was sent 
to me from Heathfield, a tree fungus being, however, substituted for the black one 
used in the former experiments. On the 1st of November the three infusions were very 
