of the /Salmon in Fresh Water. 

 Nitrogen Balance per Fish of Standard Length. 



141 



Available for liberation of energy, 10 grms. = 109,000 Kgms. 



Available for liberation of energy, 70 grms. = 763,000 Kgms. 



FEMALE FISH. 



To August Kgms. 



Energy liberated from fats, . . . 1,025,730 

 Energy liberated from proteids, . . 240,000 

 Energy from proteids to energy from fats, as 1 : 4-2.* 



To November Kgms. 



Energy liberated from fats, . . '. 1,658,460 

 Energy liberated from proteids, . . 217,000 

 Energy from proteids to energy from fats, as 1 : 7'6. 



MALE FJSH. 



To August Kgms. 



Energy liberated from -fats, . . . 1.271,400 

 Energy liberated from proteids, . . 109,000 

 Energy from proteids to energy from fats, as 1 : 11 -6 



These Tables bring out several points of very great interest. 



1 Of the fats lost from the muscle of female fish to August, only a 

 very small moiety 12per cent. goes to the ovaries, the remaining 88 per 

 cent, is available as a source of energy. Taking the metabolism 

 to November, 30 per cent, of the fats go to the ovary and 70 to energy. 



2. Of the proteids lost from the muscle to July and August in the 

 female, 23 per cent, are transferred to the ovaries, 77 per cent, are avail- 

 able for energy ; but later in the season the pro^eid lost from the muscle 

 is almost entirely transferred to and built up in the growing ovaries, 

 little or none being available for muscular energy. 



3. It thus follows that while in the earlier months the energy of 

 muscular work is derived from the fats to the extent of 8 1 per cent., 

 and from proteids to the extent of 19 per cent., during the later 

 months the fats are almost the sole source of energy. 



*If the internal fats are also considered the proportion will be 1 to 4 '9. 



