of the Salmon in Fresh Water. 109 



organs there had been fresh accumulation of fat or, in other words, if 

 the animal had been actively feeding the equilibrium would have 

 been maintained an4 the muscles would not have lost, at all events, to 

 such an extent. 



It would appear, then, that the fats taken in its food by the salmon 

 in the sea accumulate between the muscle fibres and also inside the fibres 

 between the fibril-, and that during the sojourn of the fish in the river 

 these fats steadily diminish, being either used up as a source of energy 

 by the muscle, or transported from the muscle to the growing ovaries. 

 They do not bear out Miescher Ruesch's description of the condition of 

 the muscles in the spawning fish, and they entirely oppose his view 

 that anything of the nature of a fatty degeneration occurs. 



The results of this investigation throw some light on the so-called 

 " fatty degeneration of muscle." Endless controversy has raged to 

 decide the question of direct formation of fat from proteids in the 

 cell. The results of Pettenkofer and Voit's classical experiments, the 

 evidence of the formation of fat from blood by maggots, and the fatty 

 change in the ripening of cheese have been recently dealt with by 

 Pfliiger (*) who shows that the evidence is far from conclusive. The 

 argument of " f titty degeneration of muscle" is the sheet anchor to 

 the supporters of the theory of the proteid-origin of fat. But even 

 with that their position is not secure, as has been pointed out by Dr Noel 

 Paton (t). Pathologists usually fall into the error of depending on the 

 evidence of the microscope only, without making thorough chemical 

 investigation. But it has been pointed out by Krehl (J)th;it, hearts, 

 showing the characteristic microscopic symptoms of fatty degeneration, 

 may have less than normal amount of fat. In this investigation I had 

 the advantage of comparing microscopical observations with the results 

 of careful chemical examination made by Dr. Noel Paton. 



A glance at the Figures 1, 2, and 3 will at once show that it 

 would be rather rash to come to a conclusion depending on the evidence 

 of the microscope alone. Here we have the appearance at least 

 resembling the so-called " fatty degeneration " of muscle. But how 

 can there be any fatty degeneration unless the fat is formed at the 

 expense of the proteid molecules of the muscle fibres ? The simple fact 

 that the extremely minute granules of fat are found to arrange them- 

 selve between the fibrils is no proof of their formation from the muscle 

 substance. Fraser and Bruce () have described a somewhat similar 

 appearance in the sections of the tibialis posticus muscle from a case of 

 diabetic neuritis, and called it " disseminated interfibrillary fatty 

 degeneration" ' suggt sting, at the same time, the origin of the 

 fat from the cement substance rather than the muscle fibrils. But non- 

 utilization of fat by muscles, due to failure of trophic influence of 

 nerves and want of functional activity, may lead to an accumulation of 

 fat which might be mistaken for fatty degeneration. It has been 

 shown here that microscopic appearances, such as are described by the 

 pathologists as typical of fatty degeneration, may be found in conditions 

 that are necessary in the economy of Nature. In our specimens, 

 although careful chemical examination detects no diminution of proteid 

 in the muscle substance at all events nothing like the extent which 

 would account for the enormous amount of fat there is the pseudo- 

 evidence of the microscope pointing to so-called " fatty degeneration.' 



It i^ interesting to note that in the African mud tish 

 Protopterus annectens great accumulation of fat appears in the lateral 



O Pfliiger's Arch. 52, 1 and 239. 1892. 

 (t) Journal of Physiology. Vol. XIX. No. 3. 189G. 

 ttl Deutsch. Arch. f. klin. Mod., LI., 416. 1893. 

 () Edinburgh Medical Journal, October 1896. 



