ON THE ARTIFICIAL PROPAGATION OF SALMON. 451 



the cessation of the full and vigorous action, the oscula while still immersed 

 in the water do not close entirely ; the orifices almost always remain more or 

 less open, and during this condition a comparatively languid circulation 

 continues. 



These two conditions of the animal action are strongly indicative of the 

 exertion of two distinct functions ; the vigorous action being that of the 

 period of feeding, while the gentle one indicates the breathing one only. 



If, during the powerful state of action of the sponge, we introduce a few 

 drops of water charged with indigo, the rush of the molecules to its outer 

 surface is immediate ; and if the species be Grantia ciliata or compressa, we 

 find the sponge deeply tinctured with blue in a very few minutes. After a 

 brief period we find a few molecules of indigo ejected from the common 

 faecal orifice of the sponge. 



If the sponge be now removed into fresh water, the ejection of molecules 

 of indigo continues for hours to be slowly eflFected. After having thus im- 

 bibed indigo, there is no amount of washing that will not injure the sponge 

 that will remove the colouring matter ; but if the sponge be removed into 

 fresh water, it will be found to be free from colour in a period varying from 

 twelve to twenty-four hours, the process of digestion and defecation having 

 naturally effected its removal ; and if any molecules remain on the outer sur- 

 face, a very little water poured over the sponge will now usually remove them. 



The strongly adhesive power inherent in the dermal membranes of sponges 

 and in all parts of their internal structure, readily accounts for the universal 

 habit of inosculation, not only as regards the large external branches, but 

 the internal fibres also, and it is evident that to this active power of 

 adherence the reticulated forms of fibrous structure is due. 



Report of a Committee, consisting of Sir W. Jardine, Bart., Dr. 

 Fleming, and Mr. E. Ashworth, upon the Experiments con- 

 ducted at Stormontfield, near Perth, for the artificial propagation 

 of Salmon. 



The migrations of the Salmon between the seas and rivers have long been a 

 subject of much interest to the proprietors of salmon fisheries, to sportsraen, 

 and to naturalists ; and the difficulty of making observations, or of obtaining 

 accurate information, rendered the pursuit of the inquiry if possible more 

 exciting. The experiments conducted by Mr. Shaw at Drumlanrig, and 

 Mr. Young at Invershin, produced many valuable and important results; 

 and being conducted with great care by practical men, entirely independent of 

 each other, and at stations widely apart, the facts stated were entitled to 

 every reliance. The opinions of these two men, however, were at variance 

 on a very important point, viz. the age at which the young fry assumed their 

 migratory dress and took their departure from the river to the sea — 

 Mr. Shaw making it two years, Mr. Young only twelve or thirteen months. 

 These experiments, and the success which had attended artificial propaga- 

 tion in France, and the extent to which, in that country, the latter was 

 beginning to be practised economically and for profit ; the trials of Mr. 

 Garnett at Clitheroe, and of Mr. Ashworth at Outerard in Ireland, attracted 

 the attention of the fishermen of the Tay; and on the 19th of July, 1852, a 

 meeting of the proprietors of that river was held at Perth to consider the 



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