224 STATE BOARD OF AGRICULTURE 



off by man, and nature has her way of disposing of them over which man 

 has little control. It may be asked what condition is found in under- 

 ground streams and wells. There are many springs which have their 

 source deep in the earth, the fountain of whose water may or may not be 

 free from contamination. Imagine two strata of rocks which emerge from 

 the earth at a thickly inhabited district and rich in filth. From this spot 

 the water may percolate through the soil between the strati of rocks and 

 in time find its exit in a sparkling spring of water. It is a matter of quite 

 common occurrence to find living infusoria in such water which are gener- 

 ally traceable to a source of surface water. How much easier it would be 

 for bacteria to find their way! What applies to a spring, applies equally 

 to a well; and many times wells are discovered to be the receptacle of a 

 back-yard cesspool. Rain water is usually comparatively free from injuri- 

 ous bacteria, provided the cistern is clean and the first dash from the roof 



during a rain storm be turned into the waste pipes. 

 Soil. While in some respects soil does not bear so much interest 



as water, iri others it conveys a richness of interest to our minds 

 which neither air nor water has presented. In the early days of bacteri- 

 ology little was thought of bacteria in connection with growing crops; now 

 it promises to be one of the richest as well as most formidable branches of 

 bacteriology. Every new fact that comes to light in connection with 

 nitrifying bacteria signifies the possibilities of this line of work. When 

 the farmer spreads broadcast his barnyard manure or his blacking upon 

 his fields, he does not add so many chemical constituents as he does bac- 

 teria which will change his soil to profitable and utilizable fields. The 

 nitrogen of nature which was growing so scarce before the eccentricities of 

 the nitrifying bacteria were known, will doubtless cease to be a speculative 

 element in the presence of this class of bacteria. Not only does the soil 

 furnish nitrifying bacteria but also putrifying and other fermenting bac- 

 teria. In a heap of compost there will be found millions of bacteria at 

 work upon the material forming it. Each species represents a specific 

 function to a certain degree. The slops in the back-yard, the decaying 

 matter stored in the cellar, the putrifying material scattered about the lot, — 

 all are the homes of bacteria. The city soil, where there is so much filth, 

 incubates bacteria day and night, and the ground is burdened with them. 

 Here is the home of the tetanus bacillus which gives rise to lockjaw, here 

 the typhoid bacillus sojourns, and here the source of many other infectious 

 bacteria. A pasture upon which cattle diseased with anthrax have died 

 may harbor the bacillus for years. The bacillus of blackleg also lives in 

 the soil and finds its way into the tissues with little difl&culty. Dissemina- 

 ted through the soil are bacteria of nearly every kind, from those useful 

 to man to those the most detrimental. In the old inhabited districts of 

 Europe, where filth has accumulated for centuries, some of these most in- 

 jurious bacteria may be found in large numbers. In such localities it is 

 not. infrequent for a lad to run a rusty nail of the soil into his foot and die 

 in 'a short time of lockjaw. The anthrax districts are well defined in 

 Europe; maps are made designating the exact positions of these places. 

 This is also true of blackleg, but the districts are not so well defined. 

 There are sporadic cases which can usually be accounted for in each in- 

 stance by some peculiar circumstances. A field unbroken by the plow 

 and untrampled by animals with infectious diseases contains little danger 

 from its supply of bacteria, for they are of the variety which do no harm 

 pathogenically. Sandy tracts of land have few bacteria owing to the 



