DISINFECTANTS AND DISINFECTION. 179 



benzine, etc., the sulphur dioxide is generated upon a special boat or float 

 which is run alongside and the fumes conducted into the hold of the ship 

 to be disinfected. The sulphur fumes kill all organisms present^ including 

 fleas, rats and mice. In fact sulphuring of ships must be resorted to quite 

 frequently for the sole purpose of killing rats and mice, even though there 

 may have been no disease on board. 



4. Purification and Sterilization of Water Supplies. 



Every city, town, hamlet and home should have an ample supply of 

 pure water for drinking, cooking and cleansing purposes. Impure waters, 

 that is waters which require sterilization in order to render them potable, 

 are always dangerous. It is therefore of prime importance to secure a pure 

 supply of water, sufficiently pure to make the work of sterilization and 

 purification wholly unnecessary; if that is not possible, and it generally is 

 not, under our peculiar communal condition, then said questionable water 

 supply should be thoroughly sterilized and purified, according to the most 

 approved modern methods. We cannot condemn too strongly the generally 

 prevalent methods of emptying the sewage of our cities and towns into 

 rivers and lakes and then again supplying this sewage contaminated water 

 to towns and cities for drinking and cooking purposes. There should be 

 an efficient state board of health cooperating with a Federal department, 

 and there should be efficient and competent sanitary inspectors to look after 

 the water supplies of private homes, of towns and in the country. 



The suitability of water for drinking purposes is inversely proportional 

 to the number of bacteria present. Pure spring or well water contains 

 very few bacteria, rarely exceeding 50 per c.c. Sewage contaminated water, 

 which is still used for drinking and cooking purposes, may contain several 

 million bacteria per c.c. It has been proven time and again (statistically) 

 that the mortality rate (due to disease) of cities is practically proportional 

 to the purity of the drinking water supply. It is self evident that water 

 purification should be considered a subject of the utmost importance. It 

 should receive more attention than it does. 



The sedimentation and filtration method for removing dirt, sand and other 

 coarser particles from the water supplies of large cities is practised and has 

 been practised for years in many of the European cities. This is satisfactory 

 as far as it goes, but it does not go far enough. The filtering material used 

 (sand, charcoal, etc.) does not remove bacteria and other small organisms, 

 excepting those which are attached to the coarser particles remaining upon 

 the filtering material. Furthermore, unless the filter is frequently changed 

 or sterilized, the filtering material will become the breeding place of germs 

 and thus contaminate the water still more. 



Various chemical disinfectants have been tried, but most of them have 



