BY THE HON. W. F. TAYLOR, M.D., ETC. 55 



The manufacturers claim that the Berkefield Filter possesses the 

 following advantages : — 



1. It will filter large and small quantities, according to 

 pressure and number of cylinders. 



2. The filtered liquid is absolutely free from solid particles 

 and from germs. 



3. The filter can easily be cleansed, as all impurities remain 

 on the surface owing to the density of the material. One cylin- 

 der will last for years. 



4. Each cylinder can be thoroughly sterilised by being 

 placed in warm water, and boiled for an hour. 



Test organisms were completely arrested by this filter, but 

 on the third day, in the case of tap water containing 35 io 40 

 organisms suspended in one c.c. the filtrate contained 60 per c.c. 

 and on the fourth day 200 to 300. However, inasmuch as this 

 filter completely arrests test organisms the conclusion is that 

 it affords a sufficient safeguard against the passage of disease 

 germs. 



Aeri-Filtre-Mallie Porcelaine D'Amiante. — The filternig 

 medium used in the manufacture of these filters consists of some 

 specially prepared unglazed porcelain, the pores of which are 

 very fine. This filter is impervious to test organisms, such as 

 Staphylococcus pyogenes aureus, yeasts, cholera bacillus and 

 typhoid bacillus, and completely arrests the organisms found in 

 tap water. It, therefore, affords a complete safeguard against 

 the communication of water-borne disease, but it has the draw- 

 back of filtering very slowly except tmder high pressure, and is 

 consequently not very suitable as a table filter. 



I have been at some little trouble to induce our importers 

 to send for a supply of the Chamberland-Pasteur filters, and I 

 am glad to say that one firm has sent an order for some samples, 

 I have ordered through this firm a tap filter, and hope in the 

 future to be independent to a great extent on the degree of 

 impurity of the tap water supplied to me. These filters are not 

 expensive. The tap filter I have ordered will not cost much 

 more than three pounds. I would have liked to-night to have 

 said something about the means of preventing the pollution of 

 tank water, and what means should, in my opinion, be adopted 

 in order to msure a public supply of good wholesome water — but 



