LONGEVITY OF B. TYPHOSUS OUTSIDE OF HUMAN BODY. 183 
natural fields, gardens, etc., and placed on a veranda exposed to cold 
and light. In some instances the samples were moistened with rain 
water proportionately to the precipitation at the time. Their experi- 
ments were very numerous and can not be given here in full, but the 
following are some of their important findings. Inoculating the soil 
with an emulsion of typhoid bacilli free from nutrient material, and 
keeping it moist with rain water, they were able to recover the bacillus 
up to the sixty-seventh day, and up to the fifty-fifth day even when 
the ground had been frozen part of the time and the average tempera- 
ture was 9° C. Using sterilo dilute sewage for moistening, this period 
was increased to seventy-four days at an average temperature of 
17.7° C. Using the soil from around a drain inoculated with the 
emulsion as before and moistened with raw sewage (free from B. 
typhosus), the organism was recovered after sixty-five days, although 
the ground had been frozen for several days. In soil fouled by sewage 
and kept from air and light the bacillus lived forty-five and fifty-three 
days, respectively, in different experiments, freezing having occurred 
during the former. In peat kept moist, the bacillus lived only ten or 
eleven days, in fine sand kept moist only thirteen days. In dried soils 
the bacillus did not persist as long as in moist, but lived twenty-five 
days after the completion of the drying to such consistency as to be 
blown about as dust. Under the influence of flooding the bacillus 
penetrated the intact earth to a depth of 18 inches but not of 2 feet. 
The soil was closely packed. To determine the influence of sun- 
shine, infected soil was exposed to this agent and the bacillus isolated 
from it after twenty days, during which it had received direct sun- 
shine for one hundred and twenty-two hours. Only the superficial 
layers were examined. 
Pfuhl (1902) succeeded in demonstrating a viability of 88 days in 
moist earth at a temperature of 1.5° to 15° C. In dry sand, however, 
it lived but twenty-eight days. 
' Martin (1899-1900) found a shorter period of viability, but his 
methods of isolation were not very searching. He apparently reports 
finding it after fifty days on one occasion in moist or flooded soil, but 
repudiates this finding in a subsequent report. Where very little 
moisture was present and the temperature varied from 2° to 12° C., 
it was found after twelve days, but was absent after twenty days. 
The same observer was able to isolate it from sterilized soil after 
four hundred and fifty-six days. 
Klein (1898-99) attempted to determine the longevity of B. typhosus 
in buried cadavers, using guinea pigs killed by intraperitoneal injec- 
tions of typhoid cultures. On exhumation, the washings of the 
peritoneum were examined for the bacillus. In animals buried in sand, 
he was unable to find the organism after fourteen days, although he 
