RIGOR MORTIS. 451 



both appear to be in some degree dependent upon the vital condition of the 

 body at the time. of death. When the fatal termination has supervened on slow 

 and wasting disease, occasioning great general depression of the vital powers, 

 the rigidity usually developes itself very early, and lasts for a short time. In 

 diseases which powerfully affect the nervous energy, such as Typhus, this is 

 often the case ; even though they have not been of long duration. Thus, 

 after death from Typhus, the limbs have been sometimes known to stiffen 

 within fifteen or twenty minutes. The same is observed in infants and in old 

 people. On the other hand, where the general energy has been retained up 

 to a short period before death, the rigidity is much later in coming on, and 

 lasts longer; this happens, for example, in many cases of Asphyxia and Poi- 

 soning, in which it has been said not to occur at all. The commencement of 

 the rigidity, however, is not usually prolonged much beyond seven hours ; 

 but twenty or even thirty hours may elapse, before it shows itself. Its gene- 

 ral duration is from twenty-four to thirty-six hours ; but it may pass off much 

 more rapidly ; or it may be prolonged through several days. An attempt has 

 been made to connect it with the lowering of the temperature of the dead 

 body ; but with this it does not seem to have any relation. It occurs in cold- 

 blooded Vertebrata, and even in Invertebrata, as well as in warm-blooded ani- 

 mals ; and it has frequently been noticed to commence in the latter, long be- 

 fore the heat has entirely departed from the body. Moreover, it appears first 

 upon the trunk, which is the region last deserted by the caloric. It first affects 

 the neck and lower jaw, and seems gradually to travel downwards ; but ac- 

 cording to some observers, the lower extremities are stiffened before the upper. 

 In its departure, which is immediately followed by decomposition, the same 

 order is observed. It affects all the muscles nearly alike ; but the flexors are 

 usually more contracted than the extensors, so that the fingers are somewhat 

 flexed on the palm, and the fore-arm on the arm; and the lower jaw, if pre- 

 viously drooping, is commonly drawn firmly against the upper. It is remark- 

 able, that it is equally intense in muscles which have been paralyzed by He- 

 miplegia ; provided that no considerable change has taken place in their 

 nutrition. When very strong, it renders the muscles prominent, as in volun- 

 tary contraction. 



596. The ordinary Irritability of the muscles appears to be almost invaria- 

 bly lost, or greatly diminished, before the Rigor Mortis commences. This 

 statement holds good in regard to animals of different classes, as well as with 

 respect to Man under various conditions. Thus, in Birds, whose muscles 

 most speedily lose their contractility, the cadaveric rigidity is most quickly 

 exhibited ; whilst in Reptiles it is much longer in commencing, the irritability 

 of the muscles being more persistent. The interval between the cessation of 

 the Irritability and the accession of the Rigidity, is sometimes very consider- 

 able ; and in such cases, the rigidity, when it does occur, is usually very de- 

 cided and prolonged. An attempt has been made to show a correspondence 

 between the rigor mortis, and the coagulation of the blood in the vessels ; and 

 there is certainly evidence enough to make it appear, that some analogy exists 

 between these two actions, though they are far from being identical. After 

 those forms of death in which the blood does not coagulate, or coagulates 

 feebly, the rigidity commonly manifests itself least ; but this is by no means 

 an invariable rule. It seems probable that, as the coagulation of the blood 

 will be shown to be the last act of its vitality, so the stiffening of the muscles 

 is the expiring effort of theirs. 



a. It is necessary to bear in mind, when the pftnomena of cadaveric rigidity are brought 

 into question in juridical investigations, that a state at first sight corresponding to it may 

 supervene immediately upon death, from some peculiar condition of the nervous and muscular 

 systems at the moment. This has been observed in some cases of Asphyxia; but chiefly 

 when death has resulted from apoplexy following chronic ramollissement of the brain or spinal 



