The origin of the incessant rhythmical heartbeat and the mechanism of muscle contraction have fascinated scientists over centuries. This short review outlines physiological explanations that were discussed in the 19th century starting with Albrecht von Haller (1708–1777), an 18th century physiologist who proposed that the heart has an intrinsic irritability. He argued that under normal conditions the inflow of blood stimulates the heart muscle to contract by mechanical touch and distension. Johannes Müller (1800–1858, physiologist in Bonn and Berlin) contended that the influence of the sympathetic nerve, specifically the activity of intracardiac ganglia, is the foremost cause of the heartbeat. Walter H. Gaskell and Theodor Engelmann (physiologists in Cambridge and Utrecht, respectively) independently criticized this neurogenic theory. They reported experimental evidence that supported the myogenic theory of the origin of the heartbeat, which has been accepted since about 1900. The concept of cardiac mechano-sensitivity, which can be traced back to A. von Haller, is currently resurging. Concerning mechanisms of contraction, Edward A. Schäfer (1850–1935), histologist and physiologist in Edinburgh, described differences between cardiac and skeletal muscle and coined the term sarcomere. Based on microscopic studies of cross-striated muscle, Schäfer outlined a detailed and plausible mechanism of muscle contraction in 1892. He put forward that during muscle shortening the “clear part of the muscle substance” (actin) might pass into longitudinal canals, which exist between the “sarcous elements” (myosin). His model foresaw fundamental elements of the sliding filament model, which was discovered by the Huxleys about 60 years later.

几个世纪以来，不断有节奏的心跳的起源和肌肉收缩的机制一直让科学家着迷。这篇简短的评论概述了 19 世纪从阿尔布雷希特·冯·哈勒（Albrecht von Haller，1708-1777 年）开始讨论的生理学解释，他是 18 世纪的生理学家，他提出心脏具有内在的易怒性。他认为，在正常情况下，血液的流入会刺激心肌通过机械接触和扩张而收缩。Johannes Müller（1800-1858，波恩和柏林的生理学家）认为交感神经的影响，特别是心内神经节的活动，是心跳的首要原因。Walter H. Gaskell 和 Theodor Engelmann（分别在剑桥和乌得勒支的生理学家）独立地批评了这种神经源性理论。他们报告了支持心跳起源的肌源性理论的实验证据，该理论自 1900 年左右就被接受。心脏机械敏感性的概念可以追溯到 A. von Haller，目前正在重新兴起。关于收缩机制，爱丁堡的组织学家和生理学家 Edward A. Schäfer (1850-1935) 描述了心肌和骨骼肌之间的差异，并创造了肌节这个术语。基于对横纹肌的显微研究，Schäfer 在 1892 年概述了肌肉收缩的详细而合理的机制。之间的“肌肉元素”（肌球蛋白）。他的模型预见了滑动细丝模型的基本要素，