40 



way. The supply of pure water for piibKc uses is thus a matter of fist impor- 

 tance to every community. 



It is now certain that wells, no matter how cons'ructed and whether in city, 

 town or country, cannot be depended on for purity. Surface drainage will, 

 more or less, fiad its way into them and the more numerous the houses the more 

 certaiu they are to be polluted. Hence the propriety of closing by law city and 

 town wells aud of obtaining by public works water of the maximum purity 

 from large rivers or lakes. Where this has been done the public health has been 

 promoted and the death rate diminished. 



The purity of water may easily be determined by chemical analysis in so 

 far as it depends on chemical elements, but something more than this is necessary 

 to ascertain the precise character of its solid contents in which hurtful ingredients, 

 may lurk. This is the work of the Naturalist, and uatil he has subjected these to 

 minute examination we cannot be certain as to the character of our water supply. 

 Tne water of the Ottawa River, from which this City obtains its supply, has been 

 carefully analysed by the public Analyst, and his report, we are happy to know, so 

 far as chemistry can determine, is very satisfactory. He informs us that it has a 

 slight yellow colour and peaty odour, contains no Calcium or Chlorides or Pho?- 

 phoric acid or Nitrates or Hydrates, a little Ammonia, only three and a half grains 

 in the gallon of solids in solution and four and a half grains of solids in suspension 

 with a fraction of Microcisms. Altogether we have an exceptionally good water, 

 which ranks superior to what, in England, is reckoned as first class. 



What we further want is a more particular knowledge of the solids in 

 suspension and of the Microcisms. They amoun*, in the six samples examined, 

 to about 4:h' grains to the gallon of 70,000 grains ; a small proportionate amount 

 certainly and might be thought scarcely worth notice. But when we consider 

 that most people use half a gallon of water every 24 hours a^jd some a great deal 

 more, it is obvious that the amount of its solid contents which we receive from 

 day to day amounts to something, especially when we know that they may have 

 great potency as deleterious germs. It may therefore be important to discover 

 their precise character. This can only be done by the aid of tlie microscope, as, 

 for the most part, they are quite invisible to the naked eye. 



The simplest M'ay to obtain this material is by attaching a bag of ordinary 

 cotton cloth to the water tap and allowing the water to run fieely through it for 

 a few hours. The cloth is then washed in a conical glass and the solid matters 

 allowed to settle. A great part of the water is then poured off leaving only 

 sufficient for moisture. The material can then be easil}' transferred to strips of 

 elass and covered for inspection. These filterings require to be frequently 

 gathered, more particularly in spring and summer. Winter filterings contain 

 few living forms and are chiefly remarkable for fragments ot rotted leaves and 

 frustules of diatoms. It was late in the summer before I began to take filterings ; 

 the best time was consequent'y p^st, and I suspect I have only secured a fraction 

 of what might be got. On the whole I have noted about 140 forms of animals 

 and vegetables, some being very abundant and some rare. The animals belong 

 t > the sub-kingdoms of the Articulata and Protozoa. My largest catch was a 

 Hirurlo medicinalis, or common leech, about 11 inches long. Of the family of 

 the Brachionrea there are thrr-e species, and curious creatures thoy are. They 

 have a lorica like a tiutle with horns and forked feet, a single rudimt-utary eye, 

 and a kind of nervous system ; also teeth, and a mouth with long ciUte or 

 bristles which when in rapid motion have the appearance of a wheel. They are 

 niale and female, have one kind of egg for tlie male aud another for the female, 

 and a third or resting spore for the winter. 



Of Rotifers I found five ditferent species. Eugena viridis were abundant 

 with crowds of minute vibratile spores doubtless of bijth plants and animals, but 

 impossible to determine. Specially to be noted were the numerous and beautiful 

 siliuious spiculi s of the Spongida, which I reckon to belong to three distinct 



