The anaerobic delayed heat-production after a tetanus

Abstract

The anaerobic delayed heat-production after a tetanus, as previously described, consisted of an earlier part, complete within 1 to 2 min., and a supposed long continued part, lasting 15 min. or more. The latter is due to a misinterpretation of the permanent increment in resting heat-rate produced by anaerobic stimulation. The 1st part is a genuine occurrence and starts at a high rate, falling rapidly to a low value. Its origin is obscure: it may be due to phosphate changes known to occur after contraction and relaxation are complete; more probably it is to be attributed to the overstimula-tion of some of the fibers of the muscle, which is known to produce a delayed formation of lactic acid. There is no sign of an endothermic process occurring at any stage in or after contraction. The partial restoration of phosphagen, after an anaerobic tetanus (Meyerhof Nachmannsohn) must, therefore, be regarded rather as a "re-stabilization" than as a "re-synthesis." A muscle kept for considerable periods in the purest N does not become inexcitable, as a nerve does.