452 



Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, 



which was completed 6 hours after death, lasted 11 hours, the 

 order of appearance and disappearance in this case "being practically 

 reversed. 



In a trout, in which one electrode was in contact with the skin 

 while the other was in the water, the fish was thrown into a strong 

 spasm, but not instantaneously killed. The skin of both sides behind 

 the point of contact of the electrode (which was near the head) 

 became deeply pigmented, the jaws and gill-covers continued to 

 move at intervals for 30 minutes, after which there were no signs of 

 life. The tetanic spasm seemed to pass off to a certain extent, but 

 as soon as the gill-covers stopped acting, the muscular irritability 

 was lost, and a strong rigor set in which lasted for nearly 15 hours. 



Another trout, which was tetanised and killed by an electric shock, 

 recovered from the spasm and passed into a rigor 2J hours after- 

 wards, which only lasted 7 hours. 



Another trout, which was killed, but not permanently tetanised by 

 the first shock, received seven other shocks, some of them of great 

 intensity. In less than an hour after the first shock rigor set in, but 

 it was of short duration, for in 20 minutes after the stiffening 

 appeared the jaw and gill-covers were relaxed, and the whole fish was 

 soft and limp 1J hours after death. 



It may be taken for granted, from the experiments made, that the 

 prolonged rigor of pithed fish is closely related with the destruction 

 of the central nervous system, but it does not necessarily follow that 

 the strength of the rigor in fish, instantaneously killed and stiffened 

 by an electric shock, has the same explanation. It is doubtless 

 possible that a single strong shock may, by destroying the nervous 

 apparatus, produce the same results as pithing, but it is also possible 

 that the appearance and duration of the rigor in fish killed by 

 electricity may be largely influenced by chemical changes in the 

 muscles. 



The observations made as to the appearance and duration of rigor 

 in the trout have been confirmed by control experiments on other 

 fish. It will be sufficient in the meantime, to refer to the behaviour 

 of the perch (Perca fiuviatilis), roach (Leuciscus rutilus), and eel 

 (Anguilla vulgaris), under conditions similar to some of those above 

 mentioned. 



In a roach, which died in an exhausted condition, there was no 

 response to mechanical stimulation, and 30 minutes after death only 

 a weak response at break, with the secondary coil at 0*0 cm. It was 

 almost impossible to say either when the rigor set in or disappeared, 

 and four hours after death the muscles of the trunk were alkaline, 

 and contained bacteria. A similar roach, which was killed by a blow 

 on the head and afterwards pithed, responded freely to mechanical 

 stimulation for 1 hour and 20 minutes. At first the movements were 



