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



discussed. It is stated by some that rigor never appears, whilst 

 others assert that the rigor which follows death by lightning is often 

 well marked and of considerable duration. From experiments made 

 with fish it seems that in some cases the rigor may be instantaneous 

 and well marked, or it may appear some time after death and be of 

 short duration, whilst in others it may resemble closely the rigor that 

 sets in after death from ordinary causes. When a trout receives a 

 sufficiently strong electric shock it is instantaneously killed, and at 

 the same moment thrown into a well-marked tetanic spasm which 

 passes directly and almost imperceptibly into rigor. A trout about 

 10 inches in length which received a strong shock* by placing one 

 electrode under the left gill-cover and the other (a chain) round the 

 tail, was thrown into a pronounced spasm which closely resembled a 

 heat rigor ; the lower jaw was depressed, the gill-covers widely opened, 

 the fins fully extended, and the trunk strongly arched. After the 

 shock the gill-covers and tail quivered two or three times, and in 

 about five minutes the muscles lost their irritability, and in three 

 minutes more were strongly acid. Ten minutes after the shock the 

 ■fins became if possible more extended than before ; this further 

 extension indicating probably the passage of the tetanic spasm into a 

 true rigor. 



In all the experiments when a sufficiently strong current was used 

 the result was the same, but on several occasions, though the current 

 was strong enough to cause death, the muscles recovered from the 

 tetanic spasm, and rigor set in about one hour and twenty minutes after- 

 wards. On other occasions, though the fish was thrown into a strong 

 spasm and seemed dead, there was in from ten to fifteen minutes com- 

 plete recovery. When fish, which had not only been killed by the 

 shock, but had apparently also passed into a strong rigor, received 

 several additional shocks not later than thirty minutes after the first, 

 the rigor disappeared, and although the muscles failed to recover their 

 irritability, rigor did not again set in for nearly an hour. This seems 

 to confirm what has already been observed by others, that rigor up to 

 a certain limit may be broken down and kept at bay for some time. 

 The breaking down of the rigor may be accounted for by supposing 

 that only a certain proportion of the fibres had stiffened, or that 

 coagulation had been incomplete. It was especially noticed that 

 when the muscles recovered from the first tetanic spasm in fish which 

 had been killed, it was impossible to bring on a second spasm suffi- 

 ciently strong to pass directly into rigor, and further that the spasm 

 which appeared in fish stimulated after death was never so well 

 marked as in fish which were simply under the influence of ether. 



* AHoltz machine was used, and the jar was 8£ inches in diameter with coatings 

 18 inches high. 



