202 
THE PHARMACEUTICAL JOURRAL AND TRANSACTIONS. [September 10, 1870. 
The most distinguished physiologists have occu¬ 
pied themselves with measuring the absolute muscu¬ 
lar force, and they have found that it is proportionate 
to the largest section of the muscle. 
Even the severed muscle exercises its capability 
of doing work, though there may be no stream of 
blood moving through it and conveying oxygen or 
combustible elements, but without any command 
from the central organ the potential energy becomes 
active force; heat is generated and carbonic acid 
evolved, together with certain other products, by 
the accumulation of which, in the interior of the 
muscle, it becomes tired. The simple removal of those 
products, by injecting a weak solution of salt, again 
sets up the capability of doing work for some time. 
The difference in the behaviour of a muscle in the 
living body from that of one severed from it is, that 
the capability of performing work continues in the 
living organism, while it is speedily exhausted in the 
muscle that has been severed from the body. 
However, the explanation of the continuance of 
the capability to perform work is not the first but 
the second question that has to be considered here. 
The duration of this state depends upon the cir¬ 
cumstance that the muscle is always being restored 
to its original condition, while the products that in¬ 
terfere with its working capability are incessantly 
removed from it; still a muscle remains for a time 
capable of performing work in the absence of all 
conditions for its nutrition. 
A frog’s heart, entirely freed from blood by inject¬ 
ing a weak solution of salt, will continue to work for 
twelve hours and more just as in the living body. 
In this condition we can scarcely compare it with 
anything else than a bent spring that gives out in 
motion the force it has acquired by its tension. The 
mechanical tension depends upon an altered position 
of the ultimate particles of the spring; the motion 
ceases when those parts have been again restored to 
their original position. In a manner quite similar, 
we see that with the mechanical effects produced by a 
muscle there is an alteration in the arrangement of 
its particles, and in the absence of all other causes 
that determine performance of work, it is impossible 
to avoid the opinion that the motion of these par¬ 
ticles is the source of muscular power just in the 
same way that the change in the condition of the 
contents of the yeast-cell is the cause of the breaking 
up of sugar in fermentation. 
It is known to physiologists that all the blood maybe 
removed from a frog by injecting a weak solution of 
■salt, and that the animal will nevertheless move, jump 
and breathe like a living frog for hours. In reality 
the animal does not, in this case, behave differently 
from its leg after separation from the body, though 
the phenomenon is one that must astonish any one 
who is not a physiologist.* 
* I recently received a letter from my friend Professor 
'O. N. Rood, ot New York, in which he communicated to me 
the following case: Professor Agassiz has been occupied for 
some time in catching sharks for the purpose of studying their 
anatomical structure, and on one occasion a shark that had 
been hooked struggled in the usual violent manner before it 
was landed; but on dissection the animal proved to be almost 
entirely destitute of blood. Closer examination showed that 
it had been attacked by a parasite, and the gills were in some 
places eaten through, so that nearly all the animal’s blood had 
been extracted, and its place taken by sea-water. Agassiz men¬ 
tioned this fact in order to show that the shai'k may retain 
its power undiminished for some long time after having lost 
nearly all its blood. 
It is indeed scarcely possible to do otherwise than 
think that the force of the most complex constituents 
of plants and animals, manifesting itself in motion, 
rests in their composition ; and that this force comes 
into action in a definite direction in consequence of 
the physiological arrangement of those constituents, 
—or, in other words, their conformation in the organs 
of the living body, which are built up of these ma¬ 
terials. 
In order to understand this, it is only necessary to 
remember that the yeast-cell, in causing fermentation, 
loses a part of its nitrogenous constituent, which does 
not in itself possess the power of causing fermenta¬ 
tion, though it acquires that power when it has 
served for the construction of a new cell, and has re¬ 
gained its original arrangement. 
It is not easy to form any conception as to whe¬ 
ther, and in what way, heat may be concerned in 
the performance of work by muscles; the difficulties 
in this respect will, perhaps, be less when we are 
better acquainted with the substances by the meta¬ 
morphosis of which muscular work is done. 
The unaltered composition of syntonin and albu¬ 
men in muscle appears to prove that there is no 
breaking up of them in the muscle, and consequently 
we must assume that it is by substances of very 
much higher tension that the performance of work 
by muscles is brought about. It may be that these 
are products which originate from albumen by the 
action of oxygen, taking up heat in their formation, 
as is the case in the formation of chloride of nitre- 
gen. The fact ascertained by Pettenkofer and Yoit, 
that, in a state of rest, there is an accumulation of 
oxygen in the body without any corresponding for¬ 
mation of carbonic acid, may perhaps be taken into 
account in regard to this point. 
It is conceivable that, in the breaking up of these 
substances, the heat taken up or rendered latent 
may be converted into its mechanical equivalent; 
in this case the performance of work must be pre¬ 
ceded, or at least accompanied, by a development of 
heat by oxidation, possibly of non-nitrogenous sul- 
stances. 
The existence of such compounds in muscle is per¬ 
haps indicated by the fact that Frankland was not 
able to determine the heat of combustion of creatin, 
because it always exploded violently in the tubes, 
just as some cyanogen compounds do when they are 
burnt with nitre or chlorate of potash. As regards 
cyanogen, we know that in its formation there is a 
very considerable amount of heat absorbed. Hov - 
ever, it must not be supposed that there is yet any 
ground for saying whether, or in what manner, 
creatin may be concerned in the production of mus¬ 
cular force. 
Helmholtz’s observation that there is a sensible 
rise of temperature in the working muscle separated 
from the living body, may perhaps lead to a solution 
of this problem when the collateral conditions of the 
rise of temperature shall have been more accurately 
ascertained. 
The most difficult thing, which may perhaps never 
be explained, is the influence of the nerves upon 
muscular work. A muscle, as an apparatus for per¬ 
forming work, evidently behaves in a manner similar 
to the apparatus for producing electricity in electric 
fish. 
In these animals electricity is produced by a me¬ 
tamorphosis in the small voltaic couples, and a cer¬ 
tain store appears always to be maintained, which 
