BACILLUS ENTERITIDIS OF KLEIN 143 
The second main reason for thinking the epidemic of 1^95 was probably 
due to bacillus enteritidis, was the discovery of the virulent spores of this supposed 
'uncommon'* organism in a particular sample of milk. Obviously, it is essential to 
ascertain the distribution of the bacillus, whether it is common or uncommon, and 
whether its spores are frequently or rarely present in food. 
In the year 1898, Klein points out that among the sources of bacillus 
enteritidis sporogenes are the evacuations ot cases of diarrhoea, sewage water, soil 
and dust polluted sewage, as also horses' dung. But normal evacuations must 
also be regarded as a source. Again, Dr. Balfour Stewart in Liverpool and 
Dr. Hewlett in London have isolated enteritidis spores from laboratory dust. 
They are also present in polluted water, e.g., the River Severn, but never in water 
supplied to the city of Liverpool. Dr. Balfour Stewart has recently drawn attention 
to the wide distribution of enteritidis sporogenes ' in quite innocent substances,'! for 
he found the spores from various samples of wheat, barley, oats, oatmeal, flour, rice, 
cornflour, etc., also from clover and various grasses. In all, ' sixty samples were 
examined, and forty-one gave an enteritidis-like growth in milk ; of these, thirty 
were fatal to guinea-pigs when inoculated, and eleven were pathogenic, but not fatal.' 
It appeared highly probable that enteritidis spores are also present in the 
atmosphere, I therefore examined the air outside the laboratory by aspirating a 
measured quantity through sterile plugs of cotton wool ; these plugs were then trans- 
ferred bodily into milk, heated and incubated anaerobically as usual. The volume 
of air analysed on the four occasions was 480, 2,500, 142, 960 litres. On cultivation 
each milk tube presented an enteritidis-like growth, the first and third cultures only 
were tested by inoculation and proved to be of normal virulence. Again, recently- 
sterilised milk exposed to the open air in sterile Petri dishes for a few hours 
frequently presents, after heating to 80 C. and anaerobic cultivation, changes 
characteristic ot enteritidis. On one occasion five Petri dishes ot sterile milk 
were exposed in the rooms of a private house for fourteen hours. After incubation 
three yielded a typical enteritidis-like growth, and contained the usual bacilli. Two 
of the cultures were inoculated, one was of normal virulence, the other pathogenic. 
Since, therefore, virulent enteritidis spores constantly occur in the atmosphere and 
in deposits of dust, the fact that they have been isolated from the surface of wheat, 
rice, &c, is not surprising. 
As the spores of enteritidis are very resistant to heat, and ' have been found 
to withstand perfectly unharmed a temperature of ioo° C. for several minutes, and 
one of 98° C. for a considerable time,'^ it is not improbable that in some cooked 
dishes prepared from flour, oatmeal, &c, the spores survive. For example, Stewart 
* Medical Officer's Report, Local Government Board, 1895-96, p. 204. 
t Thompson Tales Laboratories Report, vol. iii, p. 31. 
X Medical Officers' s Report, Local Government Board, 1898-99, p. 336. 
