204 ANNUAL OF SCIENTIFIC DISCOVERY. 



acid, diluted with an equal volume of distilled water. The capsules, 

 crucibles, tubes, and all the instruments employed, were also washed 

 with nitric acid. The blood was carefully evaporated to dryness in a 

 porcelain capsule, and burnt in a crucible ; the ash was treated with 

 nitric acid ; the solution was evaporated to get rid of the greater part 

 of the acids, then treated with water, filtered into a bottle, subjected to 

 the action of hydrflsulphuric acid in a small porcelain capsule, treated 

 with a few drops of aqua regia, and allowed to stand till the . precipi- 

 tate became of the color of sulphur. When analyzed, it had all the 

 properties of a salt of copper. The author therefore thinks that the 

 existence of copper in the blood cannot be questioned. 



THE AIR AND WATER OF TOWNS. 



IN the Proceedings of the British Association we find an interest- 

 ing report by Dr. Smith, on the air and water of towns. The author, 

 after remarking on the general and well founded belief that the air 

 and water have a most important influence upon health, proceeds to 

 examine all the sources from which the air and water of towns can be 

 contaminated, and the changes which are caused by them. If air be 

 passed through water, a certain amount of the organic matter poured 

 off from the lungs is to be detected in it. By continuing this experi- 

 ment for three months, Dr. Smith detected sulphuric acid, chlorine, 

 and a substance resembling impure albumen. These substances are 

 constantly being condensed upon cold bodies ; and in a warm atmos- 

 phere the albuminous matter very soon putrefies and emits disagree- 

 able odors. By oxidation this substance gives rise to carbonic acid, 

 ammonia, sulphuretted hydrogen, and probably to other gases. By 

 collecting the moisture of a crowded room by means of cold glasses, 

 and also dew in the open air, it was found that the former was thick 

 and oily, capable of decomposition and productive of animalcules, 

 while the dew was beautifully clear and limpid. Large quantities of 

 rain-water have been examined by Dr. Smith, and he says, " I am 

 now satisfied that dust even comes down with the purest rain, and 

 that it is simply coal-ashes." The rain-water of Manchester is con- 

 siderably harder than that from the neighbouring hills. This can 

 only arise from the ingredients obtained in the town atmosphere ; but 

 the most curious point is the fact, that organic matter is never absent, 

 although the rain continues for several days. The state of the air is 

 closely connected with that of the water ; what the air contains the 

 water may absorb, and what the water has dissolved or absorbed, it 

 may give out to the air. Dr. Smith has examined many wells in 

 Manchester, and he finds nitrates in all of them ; in some they exist 

 to a surprising extent, so that they are very nauseous. It was dis- 

 covered that all organic matter in filtrating through the soil is very 

 rapidly oxidized. The nitrates are also found in the London water, 

 and prevent the formation of any vegetable matter, so that none can 

 be detected, even by the microscope, after a long period. In sum- 

 ming up the results obtained, Dr. Smith remarks that the pollution 

 of air in crowded rooms is really owing to organic matter, and not 



