1887.J 



and its Relation to Putrefaction. 



453 



vigorous, e.g., when held in the vertical position half an hour after 

 death, all the swimming movements were repeated. At 1 hour and 

 40 minutes after death the muscles responded with the secondary coil 

 at 15 cm., and they still responded 9 hours afterwards with the 

 secondary coil at 0*0 cm. Soon after the irritability of the muscles 

 was lost, rigor set in, and extended slowly backwards without produc- 

 ing very marked extension of the fins, and was completed about 

 19 hours after death. The rigor persisted unaltered for 11 hours, 

 when it slowly vanished in the same order as it appeared, leaving the 

 anterior two- thirds of the fish quite flexible about 36 hours after death, 

 but remaining in the posterior third for nearly 7 hours longer. 'The 

 temperature in both cases varied from 11° C. to 12° C. 



When a somewhat exhausted roach was placed in water at a 

 temperature of 35° C, the muscles rapidly lost their irritability and 

 the rigor set in 30 minutes after death, was well established in 45 

 minutes, and was disappearing 2 hours after death, and quite off 

 2 hours 45 minutes after death. 



At a temperature of 20° C. the rigor set in 1 hour and 30 minutes 

 after death, and had all but passed off 4 hours after death. At 

 a temperature of —1° C. the rigor came on extremely slowly. On 

 placing several roach in water at a temperature of —1° C. and taking 

 them out at intervals, I came to the conclusion that in small roach the 

 rigor set in between 24 and 27 hours after death. In roach which 

 had been in water at a temperature of —1° C. for 9 days, the rigor 

 persisted for several hours after thawing, even when this was done 

 very slowly. In the perch, generally speaking, the irritability of the 

 muscles lasts longer the later the rigor is in appearing ; e.g., in a perch 

 about 11 inches in length, which had been killed and pithed, the muscles 

 were slightly irritable 13 hours after death, and the rigor was only 

 fully established 9 hours later, and it had only disappeared from the 

 anterior two-thirds of the fish 48 hours after death. But even a 

 vigorous perch, if allowed to die in the usual way, may lose its 

 muscular irritability and pass into rigor 2| hours after death, and 

 become flexible again 16 — 18 hours after death, at a temperature of 

 11-5° C. 



5. The Disappearance of Rigor. 



It has long been admitted that there is some relation between the 

 disappearance of rigor and the beginning of putrefaction, that in fact 

 putrefaction assists in driving away the rigor. While endeavouring 

 to discover a simple means for preserving fish in a fresh condition 

 last autumn, it occurred to me that there might be a closer relation 

 between rigor and putrefaction than had hitherto been determined, 

 and that it might in fact be possible to prevent putrefaction by main- 

 taining the post-mortem rigidity of the muscles In order to ascer- 



