ix THE MUSCLE-ALBUMINS 387 



Fishes : in addition to these two principal proteids, soluble myo- 

 gen-fibrin and myoproteid (in large quantities) occur. 



Amphibians : like fishes, except that myoproteid is only present in 

 traces. 



Reptiles, birds, animals : myoproteid is absent, and soluble 

 myogen-fibrin is only present where rigor mortis commences. 



According to Steyrer, 1 paramyosinogen increases in muscle which 

 is degenerating after the division of its motor nerve, while it 

 decreases after prolonged tetanisation. 



There are, however, as yet, a whole number of unexplained points 

 in the chemistry of the muscle-albumins, and nowhere does the in- 

 sufficiency of our methods for separating different albumins make 

 itself so much felt as just in the case of the muscle-albumins, for 

 they are very apt to change their properties in the course of the 

 investigation. 



. Not even the existence of two coagulable substances is beyond 

 iispute, for the differences which have been observed may well be ex- 

 plained on the assumption that one of the substances is a free albumin, 

 svhile the other is a salt of the albumin. Palladin has shown (see 

 p. 374) that the so-called myosin of many seeds is simply a lime-salt 

 }f vitelline, and that the coagulation- temperature of vitelline is lowered 

 15 by the conversion into a lime salt. It is quite possible that 

 inalogous conditions prevail in muscle. If, therefore, later on, para- 

 nayosinogen and myosinogen are enumerated separately, this is done 

 with due reserve (Cohnheim). 



A series of investigations has been made into that mixture of 

 soluble muscle-albumins which is extracted by acids and to which the 

 lame of syntonin has been given. The dissociation-products of myosin 

 lave been studied by Hart and Cohnheim (see table p. 71, No. 8), 

 vhile its acid and metallic salts were investigated by Danilevsky 2 

 md Chittenden and Whitehouse. 3 By peptic digestion myosin is 

 apidly made soluble, because it is readily converted into acid- 

 ilbumin, but having once been rendered soluble, all further change is 

 ilow, because a large proportion separates out as ' anti-albumid.' 4 

 Chis also occurs during peptic digestion. According to Danilevsky 



1 A. Steyrer, Hofmeister's Beitrage, 4. 234 (1902). 



2 A. Danilevsky, ZentralbL f. d. tried. Wissensch. 1880, p. 929 ; Zeitschr. /. 

 )hysioL Chem. 5. 158 (1881). 



3 R. H. Chittenden and H. Whitehouse, Yale Univers. 2. 95 [according to Malys 

 Tahresber.f. Tierchemie, 17. 11 (1887)]. 



4 W. Kiihne and R. H. Chittenden, Zeitschr. f. Biol. 25. 358 (1889) ; R. H. 

 Jhittenden and R. Goodwin, Journ. of Physiol. 12. 34 (1891). 



