Directory_and_Chronicle_1902 — Page 1593

1040

THE

BUSINESS NOTICES

BERKEFELD-FILTER.

No water ought to be employed for drinking or culinary purposes by human beings, which has not been perfectly purifled. We know that some, at least, of the most serious of the zymotic diseases are most commonly transmitted by their germs gaining access to, and polluting the water. There are two methods of sterilization, either boiling or filtering the water.

The process of boiling kills the germs, but the boiled water is rendered uupalatable, owing to the process expelling the dissolved gases which help to give the water its gratifying taste and freshness. Nevertheless the boiling was used because no filtering medium existed whose pores were sufficiently minute to be impassable by the minute germs, but sufficiently numerous to give a practicable quantity of

water.

The Berkefeld-Filter however fulfills both requirements perfectly and abundantly. The photograph of a particle of the filtering material as scen under the microscope, magnified 800 times, shows ladder-like and interlacing skeletons of diatomacer, giving an enormous number of exceedingly small pores, thus affording a free pussage for the liquid and at the same time arresting all minute suspended organic or inorganic matter on the surface, from which the deposits can be easily washed or brushed away.

The Berkefeld-Filter has been treated in nearly all Hygienic Institutes and many Hospitals, and is in use in the Royal Institute for Infective Diseases, Berlin; City Hospital Berlin; Hygienic Institutes of the Universities of Berlin, Bologna, Breslan, Florence, Koenigsberg, Leipzig, Marburg, Rostock, etc.

Nearly all principal Newspapers and Periodicals have written favourable articles of the Berkefold-Filter.

TEST OF WATER FILTERS made by Surgeon-General Dr. Plagge, and published by the Medical Division of The Royal Prussian War Department (Vol. IX, 1895), says:—

Page 60. The Kieseleguhrfilter (System Nordtmeyer-Berkefeld) show the greatest progress made in the Filter Technik during the last ten years; they are absolutely germproof, and give a flow of filtered water 5-10 times as rapid as the Pasteur-Chamberland Filter. Since three and a half years the filter has been subjected to the most severe test and gave perfect satisfaction. Of all the filters now in existence the Berkefeld stands the highest and is the only Alter that can be recommended for military purposes.

The

The filtering medium is a hollow cylinder of burnt infusorial-earth closed at one end. water is forced to pass the walls of the cylinder from outside to inside. The excellent efficacy is cared by the innumerable microscopie pores of the filter, which possesses the following advantages :

1. It will flter large or small quantities according to pressure, and the Altered liquid will

be absolutely free from any solid particles and from germ“,

2. Each cylinder can be thoroughly sterilized by being placed in cold water, and boiled for an hour.

The filter can easily be cleaned by washing the cylinder with a sponge, piece of Loofah or a small brush under a tap or in a vessel of water, as all impurities retain on the surface owing to the density of the material. If after a long time of use, the pores of the surface are thus glued up with organic material, that a slight washing does not open them, take a hard brush and the surface will be renewed.

Digitized by

Google