The above quoted melody appears in the Christmas Oratorio with brilliant orchestral accompaniment and interludes, three trumpets, drums and two oboes being used besides the strings and organ.
Erk has collected 319 chorales in two volumes (Peters), extracted from the church cantatas, &c., and has given full particulars of the sources. Sometimes they are worked up as fugues. Thus, the tune composed by Kugelmann about 1540, and generally known in England as the “Old Hundredth,” appears in the cantata “Gottlob! nun geht das Jahr zu Ende” in the following form, the voice parts being doubled by strings, cornet, two oboes, three trombones and organ.
The choral-vorspiele published in the Peters’ edition number about 143—besides several sets of partitas or variations on chorales, and many “Varianten,” or different workings of the same vorspiel.
Although this eminently national German and Lutheran form of religious art sank deeply into Bach’s soul, and more or less influenced and coloured all his compositions for the Church, he was accused at Leipsic of being too proud to demean himself to conducting or accompanying a mere chorale!
What he did was to allow his genius full play on a form which intensely interested him, and to exhibit it in new and original aspects.
Orchestration
The orchestration of the cantatas is of great interest. It is generally known that Bach did not usually employ the orchestral instruments in the modern manner, but made each play an independent counterpoint. Thus there were as many contrapuntal parts as there were voices and instruments combined; and a cantata was described as being, for example, “in nine parts, for one oboe, two violins, one viola, one violoncello, soprano, alto, tenor, and bass voices with organ continuo,” or as a “concerto for four voices, two oboes, viola and continuo.” Sometimes, as in “Erforsche mich Gott,” there is a violin obbligato above the voice parts in the final four-part chorale. In other cantatas it is noted that the “cantus firmus (the chorale-melody) is in the soprano,” or other voice. In the opening chorus of “Herr Gott dich loben wir,” the cantus firmus is in the soprano, the other voices sing throughout, making the interludes which are usually allotted to the instruments.