February, 1910.] 



157 



Miscellaneous. 



directly it predisposes to many of other 

 diseases, especially some of those carried 

 by water. 



Water-borne diseases occur all over 

 the world, and those so carried in 

 temperate climates, such as typhoid 

 fever, are also spread in the same way 

 in the tropics, and, in addition, there 

 are dysentery and, in somejparts, cholera. 



In all these cases the germs causing 

 the disease are passed by the patients 

 with their motions on to soil. In a 

 damp soil some of them will multiply, 

 others will remain quiescent. On a dry 

 soil they may live for some time, and 

 even be carried with dust by the wind. 

 Sooner or later they may be carried to 

 water, and when swallowed by suscepti- 

 ble individuals, particularly those with 

 impaired digestion as so often occurs 

 after malaria, the germs will rapidly 

 multiply and snve rise to an attack of 

 the disease. Water-borne diseases such 

 as cholera, typhoid and dysentery are 

 therefore carried from man to man in 

 drinking water. 



This is not all, if it were, in order to 

 prevent the spread of these diseases, 

 it would be sufficient to destroy or 

 disinfect the motions of all people suffer- 

 ing from these diseases. Unfortunately 

 many persons will continue for weeks, 

 mouths, or even years, to pass the 

 germs in their motions, though they 

 have completely recovered and show 

 no symptoms at all, These persons 

 have acquired immunity, and the 

 parasites which they harbour are harm- 

 less to them, but wherever they go 

 they deposit the germs, and if these 

 germs get into water they will set up the 

 disease in persons who drink that water. 

 Such persons are known as typhoid, 

 cholera, or dysentery "carriers," and 

 in many cases have been shown to be 

 the active agents in the transmission 

 of these diseases. 



Where possible the destruction of all 

 motions is to be recommended, and 

 burning in incinerators is the best 

 method. Burial at a depth of some 18 in. 

 is also satisractory, but then there is 

 the possibility of the drainage from the 

 burial place entering the water supply. 



The water supplies in general use on 

 estates are large open ponds or tanks or 

 superficial wells, in either of these cases 

 the ground around such tanks or wells 

 must be kept clear, and no buildings, 

 native lir.es or latrines should be allowed 

 within an area of 80 times the depth of 

 the well from it. It must not be in a 

 hollow, and no stream, drain, or other 

 channel likely to be fouled with refuse 

 from houses or any public place of resort 



should be allowed to run near it, as 

 urine as well as the motions may contain 

 the germs. 



Deep wells, those which pass right 

 through at least one impervious stratum 

 of the soil are much safer. 



All wells should have a raised parapet 

 round them, and the ground should 

 be cemented round so as to foim a 

 platform sloping from the well to a cir- 

 cular channel which collects water 

 which is spilled or used in ablutions. If 

 these precautions are not taken such 

 water will run back into the well or 

 tank, and contaminate it. 



This is a special danger in places where 

 the guinea-worm occurs. This worm 

 when mature discharges its embryos if 

 water is poured over the skin where 

 the guinea- woim is protruded. These 

 embryos, therefore, are found in the 

 ablution water. It had been known for 

 many years that these embryos only 

 lived for a few days in water, but that 

 if they entered a minute fresh-water 

 civustacean — the cyclops — they lived for 

 a long time and developed, but it was 

 doubtful how they again entered man. 

 Whether it was by bathing in water 

 containing these infected cyclops or by 

 drinking it ; whether, in fact, the worm 

 entered by the skin or by the mouth 

 was the point in dispute. In West 

 Africa, where in certain times of the 

 year a large proportion of the labour is 

 disabled from this cause, the matter 

 was so serious that the London School 

 of Tropical Medicine decided to send 

 their helminthologist. Dr. R. T. Leiper, 

 at a cost to them of several hundred 

 pounds, to investigate. Dr. Leiper con- 

 clusively proved by experiments on 

 monkeys that the guinea-worm entered 

 their warm blooded host through the 

 drinking water. 



The correct form of prevention, there- 

 fore, is now quite clear, and the know- 

 ledge thus acquired was worth in saving 

 of labour far more than the cost. If we 

 succeed in preventing water used for 

 ablution from being mixed with the 

 drinking water, then infection with the 

 guinea-worm is an impossibility. Separ- 

 ate bathing places are much to be 

 desired, but even then a few people will 

 drink the water, but those only will be 

 infected. 



If, on the other hand, the wells are 

 properly protected and water used for 

 ablution is not allowed to flow back 

 into the wells, then the cyclops in the 

 water will not be infected, and the 

 people using these wells will be safe. 



Boiling of the water before use will 

 prevent most dangers, but from the 



