Fatigue

able activity already animal appear arrival attention become beginning birds blood body Borelli brain called carbonic cause changes chemical continued contraction contracture curve death diminishes effect electric energy examinations excitability exhausted experiment express eyes fact fatigue feel finger force four functions give given greater hand heart heat important increase intellectual Italy lecture less light living longer means measure mechanical memory mental mind minutes move movement muscles muscular nature necessary nerves nervous nervous system normal observed once organism passed period persons phenomena phenomenon physiologist pigeons present processes produced Professor raised rapid regarding remains respiration rest result seen sometimes stimulated substance suffer takes place temperature thing thought tion tracing weight whole writing written