When The Blood Is Up

There is only a slight difference between a street-corner blues singer and a sanctified street singer, since both need to hold a crowd and make a few bucks (no matter what they do with the money when the day is done), and as this four-disc collection of so-called guitar evangelists from the 1920s, '30s, and early '50s makes clear, playing slide for the Lord sounds pretty much like playing slide for the other side. If anything, the guitar preachers represented here might be even more out there and eccentric than their secular counterparts, making this box set a delightful addition to the standard country blues record collection. Blind Willie Johnson, the apex of the guitar evangelists, is well represented here with classic late-'20s tracks…