24 VETERINARY HYGIENE 



bouring farms. For all the farmer knew, or apparently cared, 

 anthrax or other dangerous disease might have been the cause 

 of death. On another occasion two sows were found " buried " 

 in sacks in a deep ditch, and their presence was only revealed when 

 the water drained away. Post-mortem examination showed un- 

 mistakable swine fever lesions. 



The examination of the source of supply should not be limited 

 to the immediate locality. It may be necessary to trace back a 

 stream or ditch when pollution is suspected in order to detect the 

 cause of the trouble, if such exists. 



Some sources of deliberate pollution are difficult to detect, soil 

 pipes discharging into streams and ditches are sometimes so hidden 

 that the most careful and thorough search would be necessary 

 to reveal their presence. The following instance is typical of what 

 sometimes occurs : A detached villa in the country disposed of 

 its sewage by discharging it into a large cesspit at the bottom of 

 the garden. The garden was separated from an adjoining dairy 

 farm by a ditch through which ran a small stream of water. The 

 cesspit was about three feet from the ditch, and discharged its over- 

 flow into it. The ditch ran through the hedge into the farmer's 

 cow park, and this was the water that the animals drank and through 

 which they waded daily to their milking shed. When the author 

 became acquainted with the place the pit had not been cleaned out 

 for nine years and though the sanitary authorities were fully aware 

 of the condition they seemed quite unperturbed. 



The possibility of sheep-dipping tanks leaking or draining into 

 streams and other water supplies should be considered when a site 

 is being chosen for their construction. 



Proximity of a dipping tank to a common water supply is very 

 dangerous and should not be permitted, as many sheep dips contain 

 arsenic. At least one instance is recorded where the water of a 

 stream supplying a public reservoir became polluted and the trout 

 were killed off below a dipping tank that was situated close to the 

 stream. 



Examination of Wells and Springs. The well-water supply of 

 farms and other country houses often leaves much to be desired 

 from the sanitarian's point of view. The wells are often of the 

 shallow type, that is they collect surface water, are badly con- 

 structed, imperfectly protected and, consequently, frequently liable 

 to serious pollution. Many of these wells were built before the 

 importance of clean water was understood, so that little or no 

 provision was made to exclude the surface water. Indeed, at the 

 present time there are local builders in isolated country places 



