170 



Appendices to Fourth Annual Report 



is no inflammation of the lungs ; the heart, on the other hand, undergoes 

 ' fatty degeneration,' not throughout its entire substance, but here and 

 there foci are found where this fatty transformation has taken place.* 

 ^ow, fatty degeneration is a very compion retrogressive metabolic trans- 

 formation, not only in the heart muscle, but in the muscles of the 

 body generally. These fibres, composing the red muscles, present all 

 the appearances of a muscle in a state of fatty infiltration or fatty dege- 

 neration. 



As to the exact position of the fatty granules in relation to the elements 

 of a muscular fibre, there is some doubt. Most probably they exist in 

 the cement substance between the individual fibrillse, and it is possible 

 that they may stand in some relation to the nutrition of the fibre itself, 

 so that, instead of being a metabolic product in the downward direction, 

 they may have some relation to the constructive metabolism of the fibre 

 itself. We know, from the researches of Arnold f and L. Gerlach,J that 

 the cement substance is the channel along which the sarcous substance 

 seems to receive its nutriment. Sulpindigotate of soda is deposited in 

 granules in what is regarded as the cement substance between the bundles 

 of fibrillse. 



So far I have had no opportunity of ascertaining whether the arrange- 

 ment of the blood-vessels differs in the two kinds of muscles, or whether 

 there is any difi'erence in their chemical composition, more especially as 

 regards the amount " of glycogen they contain. In mammals the red 

 muscles contain more glycogen than the pale ones. These points are 

 reserved for future research, and are not without interest, seeing that in 

 the mammal so marked diff'erences obtain in these respects. This com- 

 munication is merely a preliminary statement of some of the results 

 already obtained. 



I have made some experiments on the relative digestibility of the white 

 and red muscles, but these I reserve for a future communication. 



I am indebted to my pupil, Mr Middleton, for the excellent drawings 

 illustrating this paper. 



DESCRIPTION OF THE PLATES. 

 Plate III. 



Side view of a plaice boiled, and the skin removed, to show the distribution 

 of the red or coloured muscles. 



Plate IV. 



Fig. 1. — Side view of the great lateral red muscle in a herring after being 



boiled and the skin removed. 

 Fig. 2. — Whiting similarly treated. 



Plate V. 



Fig. 1.— -T.S. of the body of a herring, just in front of the dorsal fin, showing 



the red lateral muscle. 

 Fig. 2. — A similar section of a herring just behind the anal fin. R, red 



muscle ; D., dorsal ; Vg, ventral. 

 Fig. 3. — Transverse section of the body of a whiting. R, R', R", Red or 



coloured muscles. 



* Knoll, Uber MyocarJ. v. d, Folgen d. Vagussect. b. Tauben, Zeit f. HeilJc. i. 

 t Die Abscheidung d. indigosch, Natrons i. Muskelgeweb. Virch. Arch. 1877. 

 t Das Verlialten d. indig. Natrons i. Knorp. lebend. Thiere. Erlangeu. 1876 



