9 8 THE CHEMISTRY OF THE TISSUES AND ORGANS. 
of the nature of nucleo-proteids. He found that they are not. He was indeed 
able to obtain no nucleo-proteid at all from muscle. Pekelharing x has taken 
up the latter question, and by an improved method discovered that muscular 
tissue does contain a small amount of nucleo-proteid. He points out that on 
gastric digestion small quantities of nuclein are soluble, if the amount of 
hydrochloric acid present exceeds Od percent. Whitfield used water as an ex- 
tracting agent for any possible nucleo-proteid. Pekelharing points out that the 
water will soon become acid from sarcolactic acid, and uses dilute (0'15 per cent.) 
sodium carbonate solution instead. From such an extract the nucleo-proteid 
can be precipitated by acetic acid. From 543 grms. of flesh be obtained 2 grms. 
of nucleo-proteid. This substance produces intravascular clotting, and contains 
- 7 of phosphorus. The nuclein split off from it contains 3 - 5 per cent, of 
phosphorus, and on decomposition yields alloxuric bases, especially xanthine 
and guanine. Hypoxanthine and adenine were not found. Kossel 2 also failed 
to get adenine from muscle. 
An important research on muscle plasma and its proteids has lately 
been published by v. Ftirth. 3 He obtained the plasma from blood-free 
muscles by extracting them with physiological saline solution. This 
extract coagulates spontaneously, and the clotted proteid formed he calls 
myogen fibrin or myosin fibrin. The proteids in the muscle plasma he re- 
duces to three, namely, paramyosinogen, 17 to 22 per cent, of the total pro- 
teid ; myosinogen or myogen, 77 to 83 per cent., and traces of an albumin. 4 
My work is confirmed in its main point, namely, that there are two 
proteids in the muscle plasma, paramyosinogen and myosinogen, which 
enter into the formation of the muscle clot ; the action of a specific 
ferment to bring about this change was not specially investigated. The 
principal new fact made out is, that paramyosinogen passes into the 
condition of myosin fibrin directly ; whilst in the passage of myosinogen 
into the state of myogen fibrin, there is an intermediate soluble stage 
coagulable by heat, at the remarkably low temperature of 40° C. 5 
Paramyosinogen is described as a typical globulin, and is regarded as 
identical with Kiihne's myosin which be obtained by dropping muscle plasma 
into water. Myosinogen is described as differing from a globulin in some 
particulars, and is spoken of as a proteid sui generis. Myoglobulin is not 
regarded as a separate proteid, but as part of the myosinogen which has 
escaped coagulation. The phenomenon regarded by Chittenden and myself as 
re-coagulation of myosin is considered to be a simple re-precipitation of globulin. 
Whitfield's work on the absence of peptones and proteoses is confirmed. 
The muscle plasma from fishes' and crabs' muscle contains another proteid, 
called myo-proteid. It gives the usual proteid reactions, and is readily digested 
by gastric juice ; though precipitated by a removal of the salts by dialysis, it 
is not coagulable by heat. It is precipitable by acetic acid, but is neither a 
mucin nor a nucleo-proteid. 
In his second paper, v. Furth treats of (1) the properties (solubilities, 
1 Ztsehr.f. physiol. Chcnu, Strassburg, 1896, Bd. xxii. S. 245. 
2 Ibid. , 1886, Bd. x. S. 248. 
3 Arch. f. exper. Path. u. Pharmacol., Leipzig, 1895, Bd. xxxvi. S. 231; also ibid., 
1896, Bd. xxxvii. S. 389. 
4 J. H. Milroy (Arch. f. Hijg., Miinchen u. Leipzig, 1896, Bd. xxv. S. 154) has also made 
quantitative estimations of the various muscle proteids coagulable at different temperatures. 
5 If the reader refers to my memoir on "Muscle Plasma," he will find, on p. 186, that I 
accidentally noted this fact, though I failed to appreciate its meaning. In frogs' muscle 
plasma there is a considerable amount of this soluble myogen fibrin in a "preformed" 
condition (v. Furth). The separation of the muscle proteids by fractional heat coagulation 
fits in exactly with Brodie and Richardson's work on heat rigor ; as the temperature of a 
muscle is raised, successive shortenings occur at the coagulation temperature of each 
proteid (Proc. Roy. Soc. London, 1897, vol. lxi. p. 77). 
