(2) _Cadaveric Rigidity_ or _Rigor Mortis_.--During this condition molecular death takes place; the muscles do not respond to stimuli, but fresh defibrinated blood passed through the muscles will restore the response to stimulation, and their reaction is markedly acid. (3) _Secondary Flaccidity._--Disintegration of the muscular elements takes place, no stimuli will provoke response, and the reaction again becomes alkaline. Table showing the principal points to be noted in the period of accession of Cadaveric Rigidity and the causes which retard or hasten its appearance, or modify its duration:-- _In what does it consist?_--In a shortening and thickening of the muscles, particularly the flexors and adductors of the extremities, and elevators of the lower jaw. _Period of Invasion._--Generally in from eight to twenty hours after death. It has been known, however, to supervene within three minutes of death, but it may be delayed for sixteen or seventeen hours. _Period of Duration._--From one to nine days. Three weeks (Taylor). _Order in which the Muscles are affected._--Involuntary muscles, back of neck and lower jaw, muscles of the face, front of the neck, chest, upper extremities and then the lower extremities. _Order in which it disappears._--Back of neck, lower jaw, &c., following the course of its accession. _Effects of Exposure to Cold._--Prolonged by dry cold air, and by cold water. _Effects of Enfeebling Disease prior to Death._--Rapid in its invasion, and passing off rapidly. _Effect of a Robust Frame at Period of Death._--The accession may be prolonged; but, other things being equal, it is more strongly manifested, and continues longer. _Effects of Violent Exercise prior to Death._--Rapidly supervenes and rapidly disappears, as in soldiers killed at the end of a battle. _Effects of Poison._--Poisons which cause violent contractions for some time prior to death--strychnine, &c.--influence the rapid invasion of the _rigor mortis_, its short duration, rapidly followed by putrefaction. Where death in poisoning by strychnine is almost instantaneous, with a short convulsive stage, _rigor mortis_ comes on _rapidly_ and remains a _long_ time. 11. _Putrefaction_.--the last of the phenomena which follow death--is the resolution of the organised tissues of the body to the inorganic state. It is a gradual process, and is the result of the action of _micro-organisms, aided by moisture, air, and warmth_. Putrefaction is the only absolute sign of death having taken place. The _conditions which modify putrefaction_ are as follows:-- _External Conditions._--1. Micro-organisms; 2. Air; 3. Moisture; 4. Warmth.