132 
NATURE 
[Fune 12, 1873 
ON MUSCULAR IRRITABILITY AFTER 
SYSTEMIC DEATH* 
He object of the lecture was to put forward certain facts 
the author had learned on the phenomenon of muscular 
irritability after systemic death. Heincluded in the same study 
certain examples in which muscular irritability has for a time 
ceased, but has become re developed under new conditions, He 
thus included the study of those states which favour the continu- 
ance of irritability or which destroy it, and those coaditions 
which suspend it but do not destroy it. By this method of re- 
search 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, organic and in- 
organic. 
Effects of Cold 
Previous to the time of John Hunter it was supposed that 
cold was the most effective agent for destroying muscular irrita- 
bility. The effects of cold employed in various ways in the 
author’s experimental researches were now detailed systemati- 
cally. 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 with- 
out 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 without mechanical injury, there is a 
period in the process wie. general muscular irr.tability may be 
made manifest. He demonstrates this fact by the simple ex- 
periment of throwing a current of water heated to 120° Fahr. 
over the arterial system of the recently dead animal. If the 
surrounding temperature be high at the time of this experiment, 
the operation should be performed within a few minutes after 
death ; but if the temperature be below freezing-point, it may be 
delayed fora long period. In one experiment the author re- 
produced active muscular contraction in an animal that had lain 
dead and exposed to cold, 6° below freezing-point, for a period 
of three hours. In this case the muscles generally remained 
irritable for seven minutes after the injection of the heated water, 
while in the muscles of the limbs, by repeating the injection at 
intervals, the irritability was maintained for two hours. 
The author drew a comparison between these experimental 
results and the phenomena of muscular irritability that have 
been observed in the human subject after death bycholera. The 
movements were not conscious, nor were they promoted by 
electrical excitation ; but the flexors and extensors belonging to 
each part in which there is movement are alternately contracted 
and relaxed as if from some internal influence. 
The influence of cold in suspending without destroying mus- 
cular irritability was further evidenced by the experiment of 
subjecting some young animals to death by the process of drown- 
ing them in ice-cold water. It was shown that in the kitten the 
muscular irritability may be restored to the complete re-establish- 
ment of life after a period of two hours of apparent systemic 
death, and although the muscles when the animal is first removed 
from the water give no response to the galvanic current. This 
same continuance of irritability after apparent systemic death by 
drowning in ice-cold water has been observed in the human sub- 
ject, not in so determinate, but in an approximated degree. An 
FRE” Croonian Lecture, by Benjamin W. Richardson, M.A., M.D., 
immersed for twelve minutes in ice-cold water retained muscular 
irritability so perfectly that he recovered, regained consciousness, 
and lived for a period of seven hours. 
Commenting on the method of restoration of irritability, the 
author showed that a certain period of time is required before 
the irritability is raised from a mere passive condition, in which 
it responds only to external stimuli, inj the condition necessary 
for independent active contractility. “The change of condition 
from the passive to the active, when it does occur, is so sudden 
as to seem instantaneous at first, then it is slowly repeated. This 
rule holds good in respect to voluntary muscles and involuntary. 
It is specially true in regard to the heart, which organ, the author 
states, may perform its office under two distinct degrees of ten- 
sion or pressure—a low tension, in which the organ itself is re- 
duced in size, and moves almost insensibly ; and a full tension, 
in which it is of larger size, and moves with a sufficient power 
to impel the blood so as to overcome the arterial elasticity and 
the capillary resistance. ‘ 
Another fact bearing on {this subject is that in rapid decline 
of muscular irritability the muscles most concerned in the sup- 
port of the organic functions, namely, the heart and the muscles 
of respiration, are the last to yield up their spontaneous power ; 
but when they have lost their power, they are the last to regain 
it. To this rule there is one exception, viz., in the muscular fibre 
of the right auricle of the heart. " 
The author then explained that the degree of cold which sus- 
pended irritability is fixed within certain measures of degree, 
from 38° to 28° F’. being the most favourable degrees of exposure, 
Lffect of Motor Forces 
Cold, by the inertia it induces, suspends, under certain con- 
ditions, but does not destroy muscular irritability.. The motor 
forces, on the contrary, quicken the irritability for a brief period, 
and then completely destroy it. The mode in which all the 
motor forces act in arresting irritability is by the induction of a 
contractile state, which, once established, remains permanent. 
The author here related his experiments on the effect of the 
different forces upon the right auricle of the heart, and reported 
as the result of his observations that, while all the forces act 
ultimately alike in producing permanent contraction, the me- 
chanical excitation is much slower than the calorific ; while 
electrical excitation appears to hold an intermediate place, as if 
it were a combination of mere mechanical motion with an in- 
creased temperature. Electrical tension may nevertheless be 
increased so as to rival heat in its immediate effect on contrac- 
tion. 
The author here traced out the results of a series of short 
sharp irritations of muscle with a needle-point, and compared 
them with the effect of a blow, showing that in each case 
rigidity follows, but is much slower in development when it is 
excited by the needle. 
The influence of heat in destroying irritability by its power in 
producing permanent contraction was described from experiments 
bearing on the relation of temperature to the muscular contrac- 
tion of different animals—frogs, pigeons, and rabbits. It was 
shown that a relative rise in temperature in each class, a rise 
averaging 12° in Fahr. scale, from the natural temperature of 
the animal was the efficient for producing permanent rigidity, 
the cause of the ultimate rigidity being coagulation of the 
myosine. 
The effect of electrical excitation is in the same direction, but 
is varied according to the mode in which the excitation is per- 
formed. Discharge from the Leyden jar produces contraction, 
which is permanent or intermittent in accordance with the mass of 
the muscle and the intensity of the discharge. This fact was eluci- 
dated by reference to a series of experiments with a Leyden 
battery, placed in cascade, and the effect produced by the dis- 
charge from 96 feet of surface upon animals of different sizes 
and weights, from sheep down to pigeons, as well as on sections 
of the bodies of the same animals immediately after death, The 
experimental facts demonstrated that with an efficient discharge 
the whole muscular system of a small animal could be fixed in- 
stantly in the rigidity of death, and that the precise position of 
the animal at the period immediately preceding death was re- 
tained with such perfection, so sudden was the change, that 
nothing but physical examination by the hand could bring to the 
mind the fact that the animal had passed from life into death. 
But the same shock passed through a sheep weighing 54 
pounds produced only a temporary contraction of muscle, 
instance was adduced in which a youth who had been deeply 
cette 
