Bach the Organist

Bach’s duties as a Lutheran church organist included “preluding” on chorale (hymn) melodies and maintaining instruments. At Arnstadt Bach must also have been expected to accompany singers both at court and in church, and during these years he also carried out organ “tests.” It is unknown whether he wrote any vocal compositions at Arnstadt, but he doubtless wrote much keyboard music and developed his organ technique during these years. Compositions examined in this chapter include chorale preludes and praeludia (preludes and fugues), as well as the great Passacaglia for organ and several vocal works (cantatas) probably performed at Mühlhausen, including the so-called Actus tragicus.

Miscellaneous Organ Trios from Bach’s Leipzig Workshop

This chapter examines various independent trio movements that Johann Sebastian Bach either composed or transcribed, probably prior to the composition of the Six Sonatas for organ. The Six Trio Sonatas for Organ, BWV 525–530, were assembled for the use of Bach’s oldest son, ilhelm Friedemann, to give final polish to his organ technique. This chapter first describes the Six Trio Sonatas before discussing Bach’s miscellaneous free organ trios in more detail. It then considers Bach’s Leipzig workshop and suggests that the miscellaneous organ trios and Six Sonata variants represent a unified repertory arising from a single period of activity in Leipzig: 1725 to 1730 or so. Aside from serving as preparatory exercises for the Six Sonatas, the organ trios were used as display pieces for demonstrating the chamber music registers of the progressive Central German organ, as well as a teaching material for students like Johann Tobias Krebs and Gottfried August Homilius.

Symphonie VIII

Charles-Marie Widor continued to develop the genre of the organ symphony in his second set of four works, published as Symphonies pour orgue, opus 42 (1878–87). The introduction to this edition of Widor's Symphonie VIII includes a list of the sources, a statement of editorial policies, and information about Widor's registrations. Symphonie VIII in B Major, in six movements, is a monumental work with a performance time of about an hour. In this symphony, which at the time of composition Widor considered to be his last, he pushed organ technique to the limit and exhausted the tonal possibilities of the instrument. Also included in this edition are four appendices containing selected principal variants, with the original Prélude movement that was removed from the symphony for unknown reasons.

Cardiac output distribution in thermally dehydrated rodents

The effect of thermal dehydration (37 degrees C) on the integrated response of the circulation was studied in conscious laboratory rats and in the desert species Psammomys obesus, the latter being studied prior to and following acclimation to heat. Cardiac output (CO) and its distribution were measured using labeled microspheres with the reference organ technique. At low dehydration (7-9% body wt loss) rats showed peripheral vasodilation coincidentally with splanchnic vasoconstriction, whereas the desert species exhibited an increased CO and peripheral vasodilation with no change in splanchnic blood perfusion. At severe dehydration (10-18% body wt loss), closure of skin arteriovenous anastomoses together with splanchnic vasodilation was observed in both species. These changes were discussed in relation to plasma volume conservation mechanism and its deterioration. Acclimation to heat resulted in no change in CO, whereas blood flow to splanchnic and skin capillaries increased remarkably. Dehydration in heat-acclimated P. obesus (5-10% body wt loss) brought about a significant fall in CO. However, most organs maintained relatively stable blood flow. This might contribute to better survival during heat stress.

Implications of Prostacyclin Generation for Modulation of Vascular Tone

1. The biotransformation of arachidonic acid and prostacyclin in the circulation was studied in anaesthetized dogs, using the blood-bathed organ technique. 2. In passage through the lungs, arachidonate (50–800 μg kg−1 min−1) was transformed into prostacyclin. No thromboxane A2 or prostaglandin E2 could be detected in arterial blood. 3. In dogs treated with indomethacin (5 mg/kg), intravenous infusions of arachidonate had no cardiovascular effects and no prostacyclin was produced. Therefore, the vasodilator effects of arachidonate in vivo may be attributable to prostacyclin formation. 4. Prostacyclin, unlike prostaglandin E2, is not inactivated by passage across the lungs, and only about 50% disappears in one passage through peripheral vascular beds. 5. Thus prostacyclin released from the lungs could function as a circulating vasodilator and contribute to the regulation of blood vessel tone and blood pressure.