30 



SCIENCE. 



[Vol. VI., No. 127. 



main river, it is additioDally necessary that the 

 Bridgeport pumps be continuously operated.^ 



From causes ah'eady indicated, — namely, by 

 the more perfect utilization of wastes and 

 refuse which formerly added to soil and water 

 contamination, and by thorough sanitary su- 

 pervision and control, — it is probable that the 

 pollution of the Chicago River will be due 

 mainly, in the future, to the sewage proper of 

 the city. This, of course, will increase with 

 the increase of population and the extension 

 of the sewer system. But I estimate, that, at 

 the present time, the river and its branches 

 may be kept in a fair sanitary condition, and 

 the sewage diluted so as to be inoffensive, by 

 causing a flow of from forty-five to fifty thou- 

 sand cubic feet per minute through the canal : 

 sixty thousand cubic feet will probably be suf- 

 ficient when the population has increased to 

 seven hundred and fifty thousand. If, by the 

 time the present capacity of the canal is 

 reached, the proposed plan of converting it 

 into a ship-canal has not been reahzed, it may 

 be necessary to seek additional relief through 

 the Des Plaines River. Pumping-works at the 

 'Ogden ditch,' discharging into the Des 

 Plaines, may then be used to supplement the 

 discharge into the canal ; and for many 3'ears 

 these two systems will be adequate to prevent 

 any serious pollution of the Chicago River, 

 will protect the water-suppl}^ from contamina- 

 tion, and will relieve neighboring communities 

 along the canal and Illinois River from the 

 nuisance heretofore frequently caused by the 

 sewage-disposal of Chicago. 



John H. Rauch. 



SOILS AND HEALTH. 



The soil, especially the first few inches or 

 feet below the surface, is the ante-chamber of 

 life, — the laboratory in which operate inces- 

 santly the processes b}- which inert matter is 

 prepared for the nourishment of life. It is this, 

 because it is also the tomb of all terrestrial 

 living matter. Here is the realization of the 

 Phoenix-myth ; the slow combustion of organic 

 matter leaving a residuum, from which springs 

 the new life of succeeding generations. 



These processes of the transformation of 

 matter are the work of the low forms of micro- 

 scopic life which are known as bacteria, and 

 are gifted with the capacity of enormous and 

 immensely rapid multiplication. This world 



1 The Fullerton-Avenue conduit was constructed, and the 

 puraping-works arranged, so as to discharge the contents of 

 the north branch into the lake through the conduit, or to convey 

 lake-water into the branch. The former method is contrary to 

 the correct principles of the sewage-disposal of Chicago, and 

 must ultimately be abandoned. 



of microscopical life is vast as regards the dis- 

 tribution and number of its living entities. 

 These minute organisms are known to be inti- 

 mately connected with many of the fundamental 

 processes of the organic world, and our knowl- 

 edge of their range of activit}^ is constantly 

 increasing. 



They may be considered practically to stand 

 in close genetic relations to many diseases ; 

 but the question of absolute diff'erentiation of 

 forms with specific functions, or of the possi- 

 bility of Protean functional characteristics 

 among them, varying with their surroundings, 

 is one of the present great problems of biology. 



The great majority of pathologists now con- 

 sider the infectious, and most of the conta- 

 gious, diseases to be dependent on these low 

 forms of life ; and the tendency is, to consider 

 that certain diseases or groups of diseases ai'e 

 produced only by specific forms of bacteria. 



These organisms are wide-spread, especially 

 the various forms that are associated with 

 putrefaction and mould. Only on high moun- 

 tains, and far from land on the ocean, is the air 

 practically free from them. Elsewhere the air, 

 water, and soil teem with them. Their abun- 

 dance is necessarih^ proportionate to the amount 

 of decomposing organic matter in the neigh- 

 borhood, since they are themselves the scaven- 

 gers, on which the processes of decomposition 

 depend. 



Few people realize what an important part 

 the soil plays in our lives. The water we drink 

 (unless from cisterns) has leached through it. 

 The air we breathe is frequently loaded with its 

 dust. It is in our food. 



The soil is highly porous ; and the interstices 

 between the grains are filled with water or 

 with air, — 'ground-water' or 'ground-air.' 

 The ground-air fluctuates with the varying 

 barometric pressure, and with the rise and fall 

 of the ground-water in rainy and dr}^ seasons. 

 The ground-water flows according to the com- 

 mon laws of hj'drostatics, but with a movement 

 retarded by friction. 



A town on a river-flat is built over a con- 

 tinuous sheet of slowly moving subterranean 

 water, and most houses are built where water 

 is accessible within a few feet from the sur- 

 face. In view of the fact that our wells and 

 the cellars of our houses are in more or less 

 close proximit}^ to these centres of pollution, it 

 was thought desirable to ascertain to what ex- 

 tent the different soils act as filters in arresting 

 the spores of bacteria. This investigation, 

 which was carried out for the National board 

 of health by the writer, assisted by Dr. Smyth, 

 brought out very clearly three facts ; — 



