LONGEVITY OF B. TYPHOSUS OUTSIDE OF HUMAN BODY. 179 
the bacillus may remain viable at least four weeks imder natural 
conditions. 
A somewhat similar case is reported by Stroezner (1905), who 
isolated B. typhosus from a well four or five weeks after the falling 
sick of the third and last case in the house supplied by it. During 
the sickness of this last case the dejecta were disinfected. Identifi- 
cation of the organism was complete. The possibility of continued 
infection from the soil applies equall}^ as much as in the previous case. 
Tavel (1903) cites a case where apparently the water of a public 
supply became infected in the pipes, from negative pressure caused 
by the varying level of the system, and remained infective for sev- 
eral months in a stagnant terminal. In a single house supplied b}^ a 
private pipe arising 50 cm. from the end of this terminal, t}q)hoid 
cases recurred long after the epidemic in the tovm had subsided. 
The town epidemic occurred in the latter half of October, and no 
cases occurred there subsequently. In the house mentioned, how- 
ever, cases kept occurring, the first on October 30, and then as fol- 
lows; December 7 and 9, March 16, and April 4, 8, and 29. On 
April 30 the blind terminal was exposed and opened, and a specimen 
of the slimy water .was sent to the laboratory, where the typhoid 
organism was found in it a few days later. Identification of the 
organism was complete. In this very important contribution no 
definite period of longevity is arrived at, but the evidence is very 
strong that the water of this terminal remained infected for about 
five months. The fact that no subsequent cases appeared in the 
tovm would seem to exclude continued infection at the original site. 
The house was located at the lower part of the tovm, where negative 
pressure and reinfection from that source did not occur. It must be 
admitted, however, that contact infection is competent to explain 
the persistence of t^’phoid in this house. 
Approaching the c[uestion from a purely experimental side, Konradi 
(1904), working in 1901, obtained most remarkable results, which 
differ radically from those of most observers. His methods are not 
given in his report. He states that under certain conditions the 
pathogenic organisms outgrow the saprophytes in water. In tap 
water inoculated with typhoid spleen the typhoid bacillus was still 
living after four hundred and ninety-nine days at room temperature 
and five hundred and forty-two days at body temperature. When 
typhoid culture was added to the water, the figures were four hundred 
and ninety and four hundred and twenty days, respectively. In the 
absence of any account of the methods employed, little weight can be 
given to these results. Fehrs explains this extraordinary longeHty 
by the fact or supposition that considerable nutrient material was 
added at the same time with the bacteria, as it certainlv must have 
been when spleen pulp was UBed for inoculation. 
Pfuhl (1902) found the bacillus alive after twenty-six days in 
