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THOMPSON YATES LABORATORIES REPORT 
Believing enteritidis sporogenes is non-pathogenic to the human alimentary- 
canal, Dr Stewart suggested the following experiment. 
A litre of new milk was heated for a quarter of an hour at 8o° C, and 
incubated at 37 0 C. After twenty-four hours, it presented the changes typical 
of enteritidis. We both ate about three teaspoonfuls of the curd, which was crowded 
with the characteristic bacilli, and afterwards inoculated a large guinea-pig with 2 c.c. 
of the whey. Next day, the animal was dead with extensive oedema. The observers 
continued in normal health. I have repeatedly eaten the greater part of enteritidis- 
like milk cultures derived from food materials, which subsequently proved to be 
virulent in guinea-pigs, without evil results. 
These experiments are not convincing, but only suggestive ; firstly, because 
enteritidis does not spore in fresh virulent milk cultures, and consequently the 
bacilli may have been killed by the gastric juice ; secondly, because healthy individuals 
are usually able to resist infection by micro-organisms. 
The litre of new milk mentioned above, although not incubated anaerobically, 
produced a typical enteritidis culture of normal virulence. In this laboratory, typical 
enteritidis-like cultures have often been obtained in recently sterilised milk without 
anaerobic incubation in a Buchner's cylinder ; not because anaerobiosis is unnecessary, 
but because the process of sterilisation converts the milk into an anaerobic medium 
by driving off all or the greater part of the oxygen it has previously absorbed from 
exposure to the atmosphere. Klein has demonstrated that 'stale' milk, i.e., milk which 
has not been recently sterilised is a bad anaerobic medium because it has become 
re-charged with oxygen ; and the oxygen may be driven off by re-sterilisation. If 
two tubes of recently sterilised litmus milk are simultaneously inoculated with 
enteritidis sporogenes, heated for one quarter of an hour at 8o° C. and incubated at 
37 0 C.j the one in a Buchner's cylinder with pyrogallic acid and potash, the other 
aerobically, it will be found that the first sign of the growth of the bacilli is bleaching 
of the litmus in the lower part of each tube. But whereas the culture in the Buchner's 
cylinder will soon be totally bleached, the other becomes red at the top, and 
eventually when the formation of gas and whey is complete, the redness will extend 
in two or three days to the curd at the bottom. If now the anaerobic culture be 
removed from the Buchner's cylinder, its curd though bleached will also become 
slowly reddened by the gradual absorbtion of oxygen. That is to say, in most, if 
not all, instances the only apparent difference between two enteritidis cultures in 
recently sterilised litmus milk, incubated anaerobically and aerobically, respectively, 
is reddening of the litmus at the top of the aerobic culture. It would probably be 
found that both cultures were equally virulent to guinea-pigs. 
I have found that if a stream of sterile air is passed, for a few minutes, 
through a milk culture after inoculation with enteritidis sporogenes, and heating for 
quarter of an hour at 8o° C, the characteristic change takes place several hours later 
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