170 SALMON. 



regular arrangement of this army as is described by the 

 Prussian naturalist, since, if it at all exists, it must be liable 

 to be broken up by the multitude of enemies and dangers to 

 which these fish are exposed, and of which man and his 

 engines are not the least formidable. But after they have 

 entered the river it is uncertain how long they keep together 

 since through the summer they are found single or in small 

 parties, and accessions are made in continued arrivals, until, as 

 the autumn advances, the newly-arrived fish present a different 

 aspect, and are urged on towards a diflferent object. It has 

 been contended that of all the fish which come into fresh 

 water from the early months of the year none return to the 

 sea until they have shed their spawn, which function for the 

 most part is only performed in the winter, or from about the 

 month of November to January, although in some instances, 

 and in particular districts, it may be so early as the latter 

 part of September, or as late as in March. But there does 

 not appear any proof of this long continuance of the individual 

 adult Salmon in rivers, and the contrary seems more highly 

 probable. Thus it is admitted that in a short time after it 

 has entered the river an unfavourable change as regards its 

 plumpness and delicacy as food is perceptible; and so speedily 

 is this produced that some observers profess to be able to 

 detect it in a few hours, and it is allowed to be visible after 

 a few weeks, by which time also the parasitic animal which 

 in the sea had fastened itself to the skin has fallen from its 

 holdfast. But if so hurtful a change has taken place as can 

 be discerned in this short space of time, we can scarcely 

 suppose that the same fish will remain in such a healthy state 

 for many succeeding months as is necessary to a successful 

 effort of spawning, being also during that time exposed to a 

 succession of the same depressing influences. We add, that 

 there appears no means by which we can feel assured that a fish 

 which is known to be in perpetual movement has not retraced 

 its course to the sea, to be replaced by a new arrival, Avhich 

 circumstance is the more probable as it is known that the 

 fixed nets employed at the entrance of rivers do just as fre- 

 quently intercept those which may be coming down as those 

 which are only moving up and down with the tide. It seems 

 certain, also, from repeated observation, that after its arrival 



