Greene. — Physiological Changes in Salmon 7 



which are determined such changes as may have occurred 

 in specimens from the stations at the head of brackish 

 water and at the spawning grounds. 



Noel-Paton has assumed the rule that similar solids 

 are to each other as the cubes of similar dimensions. The 

 dimension assumed to change least in the salmon is that 

 represented by the length, i. e., the skeleton. If one as- 

 sumes that the skeletal axis does not change in length 

 while the various organs are being consumed in the mi- 

 gration, then the length measurement can safely be taken 

 as the basis of comparison. My preliminary figures indi- 

 cate that the method of comparison by the cubes of the 

 lengths can not apply to the king salmon. Within nar- 

 row limits the variation in weight is closely proportional 

 to the length. For the present illustration I have chosen 

 salmon of nearly uniform lengths, thus eliminating the 

 errors arising from computation. All have been reduced 

 to the standard length of 860 millimeters. 



A comparison of salmon from the three stations is 

 made along two lines: First, as regards the changes in 

 the gross amount of nutritive substances represented by 

 the weight of the various organs ; second, the change in 

 the percentage composition of the primary chemical con- 

 stituents of these same organs. 



Unquestionably the muscle or flesh of the salmon 

 forms the great store-house of nutritive material, espec- 

 ially of the fat. However, the skin, the liver, the diges- 

 tive organs and probably the skeleton also serve as 

 supplementary stores of energy-giving material. The 

 figures representing these changes may be computed 

 from two points of view. First, from the point of view 

 of the intrinsic interest of a strictly scientific problem; 

 second, from the point of view of the commercial, i. e., 

 economic value of the food material represented by the 

 salmon industry. 



The individual fishes chosen are two females and one 

 male from each station, namely, the sea, the head of 

 brackish water, and the spawning grounds of the Sacra- 

 mento basin. The comparison is made on the basis of 



