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Dr. B. Ward Richardson on Muscular [May 29, 



Croone, the author had nothing to say in detail ; the object of his lecture 

 was to put forward certain facts he had learned on the phenomenon of 

 muscular irritability after systemic death — that muscular irritability 

 which remains sometimes for a brief, at other times for a long period 

 after all the outward manifestations of life have ceased, and when, to the 

 common apprehension, the animal tissues are dead. He included in the 

 same study certain examples in which muscular irritability has for a time 

 ceased, but has become redeveloped under new conditions. He thus 

 included the study of those states which favour the continuance of 

 irritability or which destroy it, and those conditions which suspend it 

 but do not destroy it. By this method of research the author thinks we 

 may proceed backwards towards living irritability, and may determine 

 upon what that depends with more facility than by experimenting on the 

 phenomena of irritability in the living animal. He imagines that if he 

 knew nothing of the construction of a watch, or why for a certain time 

 a watch maintains its motion, and if he had nobody to teach him these 

 things, he might be better able to arrive at the fact he wanted by trying 

 to set the motionless watch into motion than by interfering with it 

 while it is in motion. 



The record of experimental endeavour carried out with the design 

 above explained included a review of the work of twenty-five years. 

 The subjects brought under consideration were arranged as follows : — 



(1) The effect of cold on muscular irritability after systemic death. 



(2) The effect of motor forces, mechanical, calorific, electrical. 



(3) The effect of abstracting and supplying blood. 



(4) The effect of certain chemical agents, inorganic and organic. 



Effect of Cold. 



Previous to the time of John Hunter it was supposed that cold was 

 the most effective agent for destroying muscular irritability, and to this 

 day the impression is commonly maintained ; so that the sensation of 

 cold in a motionless animal is accepted as the surest evidence of death. 

 Hunter was the first to show by direct experiment that this was an 

 error, and that cold suspends irritability without destroying it. The 

 original experiment of Hunter illustrative of this position was here 

 described. The effects of cold employed in various ways in the author's 

 experimental researches were now detailed systematically. The effect 

 of cold in suspending the muscular irritability of fish, reptiles, and frogs 

 was first described. On all these animals it was shown that cold could 

 be made to suspend without destroying the muscular irritability for a 

 long period of time, and that in fish (carp, on which the author had 

 made the greatest number of experiments) the restoration of irritability 

 could be perfected to the extent of the restoration of the living function. 



Passing to warm-blooded animals, the author showed that in the process 

 of cooling in every animal that has been suddenly deprived of life with- 



