1887.] 



and its Relation to Putrefaction. 



439 



nerves, the rigor will be purely pathological, and consist of a mere 

 fixing of the muscles in whatever position they happen to be. Another 

 important consideration is what determines the time of appearance 

 and strength of the rigor. In some instances I have been unable to 

 detect rigor, in others, it has appeared at ordinary temperatures, a. 

 few minutes after death, while in other cases it appeared from ten to 

 twenty hours after death. Again in some cases it is extremely weak 

 and of short duration, whilst in others it is well marked and pro- 

 longed. It may be safely asserted that if all the nerves in a given 

 muscle were destroyed, that muscle would still pass into rigor. But 

 although the rigor would probably set in were all the nervous ele- 

 ments destroyed, the nervous system has apparently considerable 

 influence in determining the time of appearance of rigor. Some 

 physiologists seem to believe that the rigor comes on when and 

 only when death has reached the muscles, by travelling in some 

 cases hurriedly, in others slowly, from the central nervous system 

 along the motor nerves. I hope to show that the longer the 

 central nervous system continues to act, not only will the muscles 

 sooner die, but the rigor will be the weaker and shorter, though in 

 some cases from the arching of the trunk and extension of the fins, it- 

 may appear to be otherwise. 



Let us suppose that two fish are instantaneously killed, the one- 

 in a vigorous, the other in an exhausted condition. In the former a 

 considerable time will elapse before the energy of the muscles is- 

 exhausted, before the explosive material is all used up, while in the 

 latter the muscles having already expended nearly all their energy 

 during life, and little or no new productive material having been 

 formed after death, they will soon die. Further, in the fish killed in 

 an active condition, the muscles will give rise to a well-marked lasting 

 rigor, whilst in the other it will be weak and of short duration. The 

 result of artificial exhaustion is the same as that of natural. If a 

 rabbit is killed and immediately after death the muscles of one hind 

 limb exhausted by an interrupted current, rigor sets in in the ex- 

 hausted limb two to three hours sooner than in the other. In the- 

 same way, if a fish is tetanised immediately after death, rigor sets in 

 quicker than in another fish which has escaped stimulation. But- 

 further, if two fish are killed and the central nervous system at once- 

 destroyed in one, but left intact in the other, rigor will be considerably 

 later in appearing in the pithed fish. The explanation possibly may 

 be that the central nervous system after death tends to exhaust the 

 latent energy of the muscles by constantly stimulating them into- 

 action ; while, on the other hand, when the central nervous system is 

 destroyed, the muscles are not stimulated into action, and there- 

 fore their final passage into rigor depends chiefly on the tempera- 

 ture and other surroundings. 



