of Edinburgh, Session 1871-72. 695 
the results may be useful to others, I beg to offer them to the 
Society, 
I first examined the composition of a very fine “ Clean ” fish, 
caught in the estuary of the Tay in May last year, and weighing 
20 pounds. I have never seen a finer fish from that far-famed 
salmon-river. 
I have also, in contrast with this, examined a “Foul” fish, or 
Kelt, taken in the beginning of March last from a pool where 
spawned fish are known to congregate at that season in the Isla, a 
principal tributary of the Tay. It weighed 27 pounds the day 
after it was caught, and would probably have weighed 35 pounds 
in good condition. In order to account for my being in lawful 
possession of such an article, I must mention that I owe it to the 
consent of the Commissioners for the Tay Fisheries, whose kind- 
ness in presenting, for a scientific object, what otherwise cannot be 
easily obtained without infringing the law, may receive, as I hope, 
some return in the additional proof which analysis supplies of the 
inferiority of the salmon as food when in the state of a Kelt, and 
the folly of destroying it before it recovers condition. 
The clean salmon of last May presented abundance of fat under 
the skin, and in masses betwixt the muscles. Avoiding all accu- 
mulations of fat in mass, I cut one piece of muscle from the 
dorsal region a little in front of the dorsal fin, and another from 
the ventral region directly opposite ; so that the one should repre- 
sent the “ thick,” and the other the “thin,” of a slice of salmon 
Four hundred grains of each being cut into fine chips about twelve 
hours after the fish was caught, each was separately exhausted by 
ether ; and the ether was distilled off at a gentle heat. When the 
residual oil was deprived of a little adhering alcohol and water by 
heating it gently for an hour in an open vessel, it had a bright 
amber colour, and a strong odour not very different from that of 
cod-liver oil. The fibrous residuum was dried at 212° till it ceased 
to lose weight. A portion of the dry residue was incinerated in 
order to determine the fixed saline constituents. The difference 
denoted the dry nitrogenous nutritive principles, fibrin, albumen, 
and extractive matter usually called osmazone. 
