It will help us to understand this matter if we bear in mind that the home of these bacteria is the tubercle upon the clover root. It is quite evident that they will continue to live upon the decaying tubercles or roots for three or four years after the clover plant has been killed. On the other hand, we have some notable evidence that the bacteria do not continue to live in a soil after five or six years’ continuous cropping with absolutely no clover growing on the land during those years. It is a simple matter for any one to determine whether the bacteria are present or not, for the tubercles which are formed if the bacteria are present are plainly seen attached to small roots. They look somewhat like miniature potatoes, varying in size from pinheads on clover to peas on soy beans or cowpeas. (See Plates 2 and 4.) It is important to remember that the bacteria live in the soil and not in the seed. When clover is cut for seed, it is frequently left to lie upon the ground until the straw becomes half rotten and very dirty; and, consequently when it is threshed, it practically always happens that there is at least some small amount of dust and dirt taken with the seed. This dirt is almost sure to carry with it some bacteria from the soil. If these few bacteria are scattered with the clover seed when it is sowed they will inoculate at least a few plants, and if they are allowed to multiply on these plants, and especially if the same field is repeatedly seeded with clover, the soil will ultimately become thoroughly infected with the clover bacteria. Of course they may be carried from one part of the farm to another, or even from one farm to another, by various agencies, as dust or wind storms, surface drainage or flood waters, manure made from clover hay, implements used in cultivating the soil, etc., etc. Many of the older farmers of Illinois have stated to the writer that when this country was very new it was commonly found difficult to get a “catch” of clover on new land. After a good “catch” was once gotten, then it was easier to get clover to grow on that land the next time. There was a saying among the farmers that clover would not do well until they got the “wild nature” out of the land. Their final success was undoubtedly due, not to getting anything out of the land, but rather to getting the bacteria into the land. Several Illinois farmers have reported some quite remarkable results from very light applications of the clover chaff or straw (obtained in hulling clover) in its beneficial effect on clover on land where it was otherwise difficult to get a “catch.” There is a somewhat general belief among farmers of long experience that clover straw or chaff has some special value in getting a catch of clover aside from its value as manure or for the seed which it sometimes contains.