Having thus considered the value of the tests of respiration, we shall proceed to appreciate those which have been considered as furnishing no less certain indications of death. The absence of the circulation, the impossibility of feeling the pulsations of the heart and arteries have been regarded as infallible means of deciding whether the individual be dead; but it is proved beyond all doubt that a person may live for several hours without its being possible to perceive the slightest movement in the parts just mentioned. It has been thought also, says _Orfila_, that an individual was dead when he was cold, and that he still lived if the warmth of the body was preserved; there is perhaps no sign of so little value; the drowned who may be recalled to life, are usually very cold; whilst in cases of apoplexy, and some other fatal diseases, a certain degree of warmth is preserved even for a long period after death. Stiffness of the body is another sign of death upon which great reliance has been placed; but as it sometimes happens that it exists during life, it becomes necessary to point out the difference between the stiffness of death, and that which occurs during life, in certain diseases. For the following observations upon this subject we acknowledge ourselves indebted to the judicious treatise of _Orfila_. 1. Stiffness may be very considerable in a person who has been frozen, who is not yet dead, and who may even be recalled to life. This stiffness cannot be confounded with that which is the inevitable result of death, because it is known that the body has been exposed to the action of severe cold, and above all because it is very general; in fact, the skin, breasts, the belly, and all the organs may possess the same rigidity as the muscles, a circumstance not observable in _cadaverous_ stiffness, in which the muscles alone present any degree of resistance; besides, when the skin of a frozen person is depressed, by pressing forcibly upon it with the finger, a hollow is produced which is a long time in disappearing. When the position of a frozen limb is changed, a little noise is heard, caused by the rupture of particles of ice contained in the displaced part. 2. The stiffness to which the late _M. Nysten_ has given the name of _convulsive_, and which sometimes manifests itself in violent nervous diseases, may be easily distinguished from _cadaverous_ stiffness; when a limb is stiff in consequence of convulsions, &c. the greatest difficulty is experienced in changing its direction, and when left, it immediately resumes its former position; it is not the same in stiffness from death; the limb, the direction of which has been changed, does not return to its former position.