of the Salmon, in Fresh \Y<tter. 



139 



12. THE FATS AND PROTEIDS STORED IN THE 

 MUSCLE CONSIDERED AS A SOURCE OF 

 MUSCULAR ENERGY. 



BY D. NOEL PATON, M.I). F.R.C.P.ED. 



The foregoing study of the changes in the fats and proteids affords a 

 basis for the elucidation of the part played by each of these in the 

 liberation of energy available for the muscular work of the fish. 



The fats and proteids lost from the muscles during the sojourn of the 

 fish in fresh water, over and above those accumulated in the ovaries and 

 testes, must be decomposed for the liberation of energy. 



This matter is of interest, firstly, because it shows whether the energy 

 evolved from the fats and proteids decomposed is ad equate for the needs 

 of fish during its stay in fresh water ; and, secondly, because it elucidates 

 the question, not hitherto studied by physiologists, of the source of the 

 energy in cold-blooded animals. 



The following Table shows the amount of energy in work units 

 Kilogrammebres set free from each of these substances throughout the 

 season. In these Tables the fats and the nitrogen are given in 

 grms. : 



FEMALE SALMON 1896. 

 Fat Balance per Fish of Standard Length. 



Estuary (May to August), 

 Upper Water (July and A 



August) 



Muscle. 



770 

 478 



Loss 292 



Ovaries. 



Gain 31 



Available for liberation of energy, 261 grms. = 1,025,730 Kgms. 



To this should be added about 20 grms. of fat from the pyloric 

 appendages ; and about 20 grms. of fat from the liver (see p. 100J, say 

 40 : which makes 300 grms., or 1,179,000 kgms. 



Available for liberation of energy, 422 grms. ? 1,658,460 Kgms. 



