318 ANNUAL OF SCIENTIFIC DISCOVERY. 



of salmon-ladder,* which was to obviate the difficulties complained of 

 by the millers. He then explained other difficulties, particularly 

 that of finding a grating to prevent salmon swimming up mill-races, 

 and getting injured by the mill-wheels. Xo grating had hitherto 

 been invented which at the same time would prevent the salmon run- 

 ning up and not lead back the water on to the wheel and stop its ac- 

 tion. Mr. Buckland concluded his instructive and at the same time 

 amusing paper as follows : " Thus, then, I have endeavored to bring 

 before the members of the British Association certain facts relative 

 to two great branches of British industry, the cultivation of the 

 sea, and the cultivation of the rivers ; the revenues derived from these 

 both to private owners and to the public in general in the form of food, 

 would, if put together, amount to an enormous sum, and still neither 

 industry is as yet half developed. 



In a treatise on fish-culture also recently published by Mr. Buck- 

 land, the author states, that salmon and trout carry on an average 

 1,000 eggs to one pound of their weight. Another important fact 

 respecting the eggs of some fish is their great toughness, a provision, 

 doubtless, intended to enable them to resist the crushing effect of 

 stones and gravel in their spawning beds. In order to ascertain pos- 

 itively how much direct weight trout's eggs would bear, Mr. Buck- 

 land placed iron weights upon individual eggs, which did not give 

 way until the pressure amounted to five pounds and six ounces. 



In 1861, the fish-breeding establishment instituted under the aus- 

 pices of Government, at Huningue, France, distributed upwards of 

 16,000,000 of fish-eggs, for breeding purposes over Europe. Recent 

 authorities also declare that it is cheaper and easier to breed salmon 

 than lambs. Salmon eggs, according to Mr. Buckland, preserve, 

 their vitality after having been imbedded in ice for the long period of 

 00 days ; and eggs thus treated have been successfully hatched. 



INFLUENCE OF MODERN CIVILIZATION ON HEALTH AND 



LONGEVITY. 



At a recent meeting of the Association of Medical Superintendents 

 of American Institutions for the Insane, the following remarks on the 

 above subject were submitted by Dr. Edward Jarvis, of Massachu- 



* This ladder is described by Mr. Buckland as follows : T\vo Avails are constructed 

 from the top to the loot of the weir (on its slope). Slabs of iron or stone (the 

 stops) are then fixed at right angles into these walls, reaching about four- fifths of 

 the way across the passage. The slots (or passages for the fish between the wall 

 and the end of the stop) come alternately to the right and left, so that when the 

 water runs down the ladder it describes a zigzag (or rather serpentine) course : the 

 fish no.Miig about the foot of the weir, are attracted to the foot of the ladder by 

 the current coming down it ; they then make a rush through the lowermost open- 

 ing into the first box or step, then into the next, and next, and so on till they get 

 to the top. If they are tired, they can rest as long as they please in the eddies 

 between each of the stops. It is found, however, in practice, that it does not 

 answer to make the ascent of the ladder too easy, as, if the lish find themselves 

 too comfortable in the eddies, they will stay there, and be liable to become a prey 

 to poachers, as a reward for their laziness. Thedimensions of a ladder for salmon 

 which has been introduced at Teddington, England, are given as follows: Length 

 40ft.; width (inside the walls) 4 ft.; stops 3 ft. 3 in. long, 18 in. high, and 4 ft. apart ; 

 the slots (or openings) at the ends for the fish to go through, 9 in. wide. The total 

 fall of the ladder is (} ft. or 7ft. and the incline one in seven. Up such a ladder, 

 says Mr. Buckland, the young salmon will go with such a rush that if a man and 

 a salmon were to start fairly from the bottom the latter would swim up to the top 

 faster than the man could run along the wall by its side. 



