BY THE HON. W. F. TAYLOR, M.D., ETC. 37 



of ill-health are probably owing to the use of water from these 

 tanks containing 'zinc in solution — for zinc in minute doses 

 produces a depressing effect on the system. This matter deserves 

 more attention than is given to it here, for undoubtedly the 

 constant use of galvanised iron tank water must have an inju- 

 rious effect upon the health of some individuals. Water may 

 be the source of various parasites which infest the human being, 

 among the principal may be mentioned — Hydatids, derived from 

 the tapeworm of the dog, through the egg being deposited in 

 water ; Filaria Sanguinus Hominis, from the mosquito, which 

 develops the mature sexual worm, whose eggs again occur in 

 water ; Anchylostomum duodenale, a worm which infests the upper 

 part of the small intestine, and gives rise to fatal anosmia ; 

 Bothrioeephahis latus, or tapeworm, and varieties of the Distoma, 

 The characteristic organisms of typhoid fever and cholera 

 have been found in water, it being generally recognised that 

 outbreaks of these diseases have occurred in which the proof of 

 their origin from drinking water is irrefutable. I have already 

 given an instance of a recent occurrence, where an outbreak of 

 typhoid fever was clearly traced to water contaminated by the 

 specific bacillus of the disease, and many other cases could be 

 recorded of a similar kind were it necessary to bring them for- 

 ward in support of this fact. Plenty of evidence is also forth- 

 coming to prove that cholera is spread by drinking water, 

 although some men of eminence have denied that it is so. The 

 bacillus of tubercle, the bacillus of anthrax, the bacillus of teta- 

 nus, the bacillus of scarlet fever and of diphtheria, and the strepto- 

 coccus of erysipelas, have all been found in water ; but there is 

 little or no evidence that the diseases produced by these organ- 

 isms have been more than only occasionally propagated by 

 drinking water. Diarrhoea and dysentery may be caused by the 

 use of polluted water, and malarial fever has been proved to have 

 been produced by the same cause. 



Purification. 

 It has been seen that water may be contaminated from 

 various sources ; means, therefore, should be adopted to purify it 

 before its distribution to the consumer. Among the various 

 methods in use for that purpose filter-beds afford the best means 

 of purifying water on a large scale. These are usually composed 



