322 THE MUSCLE PLASMA. [BOOK I. 



nor salicylic acid reagents which coagulate the proteids affect the 

 doubly refracting sarcous elements, so that one would be inclined 

 to believe that they consist rather of some derivative of the proteid 

 bodies than of proteid bodies pure and simple. 



It is stated that ' Krause's membrane, ' though sharing the optical 

 properties of the sarcous elements, has a different deportment towards 

 dilute acids ; thus a three-per-cent. solution of acetic and a one- 

 per-cent. solution of hydrochloric acid are said to annul the 

 anisotropous character of the sarcous elements, but not of Krause's 

 membrane, which is, however, affected by caustic alkalies in the same 

 manner as the sarcous elements. 



The Muscle Plasma 1 . 



Kiihne's 2 The ^9. u ^ to which the name of muscle plasma is 



method of given, and which constitutes, as has been shewn, the 

 obtaining isotropous material of the voluntary muscular fibre, can 



Muscle Pias- or jy be obtained from muscle which has not passed into 

 ma " the state of rigor mortis, for when this change occurs, a 



solidification of a proteid matter previously in solution occurs, and 

 muscle plasma, properly so called, ceases to exist. Cold delays the 

 coagulation of the plasma, as it does that of the liquor sanguinis, and 

 it is by its aid that the plasma can be obtained. 



The muscles of cold-blooded animals alone preserve their vitality 

 sufficiently long to permit of the plasma being removed before rigor 

 has had time to occur ; practically those of the frog are always em- 

 ployed, and the process is the following : 



The frog is bled, and salt solution (\ p.c.) is injected into the 

 aorta, so as to wash the whole of the blood out of the muscles. The 

 muscles are then cut up into small pieces, and washed in, or kneaded 

 with, more of the same salt solution cooled to C., with the object of 

 getting rid of lymph. The fragments are then collected together, 

 enclosed in fine linen, and tied up so as to constitute a compact ball, 

 which is exposed to a temperature of about 7 C. until it is in 

 such a condition that it can, by means of cooled knives, be conveni- 

 ently cut into very fine slices ; this operation can only be carried 

 out in very cold weather. The frozen slices are then pounded in 

 cooled mortars, the pounded muscle tied up in strong linen, and 

 expressed in a strong press at the temperature of the room. The 

 muscle thaws at 0, so that the liquid which flows from the press has 

 this temperature ; it is then filtered through small paper filters 

 moistened with ice-cold salt solution ; as the filters speedily clog, the 

 fluid must frequently be transferred to fresh filters. 



1 This account of the Muscle Plasma and Muscle Serum, is taken almost verbatim 

 from Kiihne's Lehrbuch der physiologischen Chemie, It would have been vain to 

 attempt to give a more succinct or a more satisfactory account than that of the eminent 

 physiologist to whom we owe almost every fact known in relation to the proteids of 

 muscle. 



2 Kiihne, Untersuchungen iiber das Protoplasma^ p. 2. Lehrbuch, p. 272. 



