PROGRESSIVE WEIGHT OF SALMON. 397 



.-and beautiful demoustration of the circulation of the 

 blood never was yet placed under the microscope. 



The average weight of a young salmon just hatched 

 is nearly two grains, forage bag and all ; he has therefore 

 a good deal to make up before he is fit to lie on Mr. 

 Groves' marble slab. 



The rate of increase of weight in the young salmon 

 according to my late lamented friend Mr. Ashworth is 

 as follows : 



" At three days old it is nearly 2 grains in weight ; 

 iit 16 months old he has increased to 2 ounces, or 480 

 times its first weight ; at 20 months old, after the smolt 

 has been a few months in the sea it becomes a grilse of 

 8-|-lbs., having increased 68 times in three or four months ; 

 iit 2f years old it becomes a salmon of 121bs. to ISlbs. 

 weight ; after which its increased rate of growth has not 

 been ascertained, but by the time it becomes 301bs. in 

 weight it has increased 115,200 times the weight it was 

 at first." 



I do not suppose there is any other animal that in- 

 creases so rapidly and at so little cost, and that becomes 

 such a valuable article of food. 



In various creatures the progress of development is 

 different ; thus, for instance, in the human baby, the 

 first portion of the body developed is the lower jaw and 

 this for an obvious reason, that is, because the most 

 material want of the baby is to obtain the mother's 

 milk by suction. Now if the lower jaw were not solid 

 and firm in vain would it try to suck. 



But in the case of the fish, nature has kindly packed 

 up all the nourishment that it will want for some six or 

 eight weeks in a neat little bag or parcel, which she has 

 affixed to the body of the fish in such a manner that it 

 shall be gradually absorbed into the general system ; 



