THEIR FUNCTION. 95 



fluid surrounding and permeating the above-described matrix of 

 the contractile fibres, which is distinguished by its acidity, and 

 differs entirely from the plasma of the blood. Liebig has calculated 

 that the voluntary muscles alone contain more than sufficient free 

 acid completely to destroy the alkalinity of the blood. We have 

 already seen that wherever contractile fibres or fibre-cells are pre- 

 sent, the potash-salts and phosphates predominate in this fluid, 

 whilst the blood-plasma, on the contrary, is poor in these salts, 

 but rich in alkaline chlorides and soda-salts. The difference 

 thus observable in the intercellular fluid of the blood-cells and 

 that of the contractile fibres cannot be merely accidental ; and 

 Liebig has suggested that it very probably either occasions, or is 

 occasioned by an electrical current. We know, however, that 

 Du Bois Reymond * has subsequently arrived at many novel views, 

 and obtained some brilliant results relating to the electrical phe- 

 nomena of muscular contraction, in repeating the observations of 

 Matteucci. The existence of an intimate connection between the 

 development of electricity accompanying muscular contractions 

 and the acid of the muscular juice on the one hand, and the alkali 

 of the blood on the other, and the importance of the chemical con- 

 stitution of the muscular juice on the function of the organ, are 

 corroborated by the striking and well-known fact, that all muscles, 

 whether voluntary or involuntary (both the striped and the 

 smooth) lose their contractility very rapidly in water. (Lukewarm 

 water at + 37 scarcely acts less rapidly on this property of mus- 

 cles than cold water.) The experiment of the younger Liebigf 

 seems opposed to this observation, which may be tested by any 

 one who watches by means of a rotatory apparatus the contraction 

 of the transversely striated muscles of a recently killed animal, or its 

 stomach, intestinal canal, bladder, &c. This observer found that 

 muscles, which had been freed as thoroughly as possible from 

 blood by the injection of water into the vessels, retained their con- 

 tractile property as long as those muscles which still contained 

 blood. These two observations do not, however, involve a contra- 

 diction ; for if the muscles do not lose their contractility in the 

 absence of blood, but do so on the addition of water, it simply 

 shows that the muscle loses its capacity for contraction by the 

 dilution of the muscular juice. If, therefore, we connect the 

 development of electricity during muscular contraction with chemi- 

 cal forces, we shall find that the causes of the phenomena of polarity 



* Unters. lib. thier. Elektricitat. Berl. 1848 u. 1849. 



t Ber. der Akad. d. Wissensch. zu Berlin, 1850, S. 339-347. 



