Fishes. 2193 



of our ignorance upon this subject, that none but the most unexceptionable evidence 

 should be received. Let us have " the truth, the whole truth, and nothing but the 

 truth." I need hardly add, that in these observations I am actuated by no unfriendly 

 feeling towards Captain Woodward : my desire is to get at the truth of the matter ; 

 and I should hail with delight the day when one of these monsters of the deep, what- 

 ever they may be (for some animal with which we are unacquainted has, I firmly be- 

 lieve, been seen), is brought to our shores and lodged in one of our museums, to be at 

 once the wonder and admiration of naturalists. — W. W, Cooper; Claines, Worcester, 

 June 2, 1848. 



' Fish in Rivers and Streams : a Treatise on the Production and Management of Fish 

 in Fresh Waters, by Artificial Spawning, Breeding and Rearing : showing also the 

 cause of the Depletion of all Rivers and Streams. By Gottlieb Boccius. 5 Lon- 

 don : Van Voorst. 1848. 



[The ample title of this little work sets forth very truthfully the subject-matter of 

 its pages. Mr. Boccius is already favorably known to the preservers of fish as the 

 author of a ' Treatise on the Management of Fresh-water Fish, with a view to making 

 them a source of Profit to Landed Proprietors ; ' and the present pamphlet follows up 

 the subject by detailing an artificial mode of procuring fry. The following quotations 

 will I think be found highly interesting. — E. iV.] 



" The main cause why all fresh-water streams become sterile in the end, if not 

 carefully tended, is simple enough ; namely, all the smaller streams form the sewers 

 of the adjacent country, and fall into the larger rivers, and the latter again act as the 

 sewers of the towns aud of the kingdom, and are carriers of their congregated impuri- 

 ties finally to the sea. The increasing population of human beings charges the rivers 

 every day with more and more foul matters, the refuse of towns and the agrarian dis- 

 tricts passing into them ; and hence the destruction of the spawn, egg, or ova of fish, 

 but not of the fish when once brought into life. One cause of this I shall explain 

 chemically. Water is composed of one volume of oxygen gas and two volumes of 

 hydrogen gas. No life can be sustained without oxygen, let it be animal or vegetable : 

 consequently, when water becomes thickened by other matters, a new compound is in- 

 troduced, which produces a new chemical action ; and this is the cause why all rivers 

 and streams eventually become barren : for the following is the result of such a con- 

 dition of waters, which it is an abuse of language any longer to call fresh. The egg 

 of a fish, in production, differs from that of other animals, as the absorption of the 

 spermatic fluids does not take place till it has passed from the parent, and is then left 

 on its bed, hill, or weed, according to the description of the fish, until the period of 

 incubation has arrived ; but in the meantime, should the water become foul and 

 change its character, then the alluvial deposit in the water settles down upon the pedi- 

 cle or neck of the egg, hermetically seals the same, and prevents the oxygen gas (the 

 component part of water) from being absorbed and passing to the embryo, from which 

 cause suffocation takes place, and the egg is, in the common phrase, addled. This 

 may seem strange ; but the student of the laws of Nature well knows that oxygen gas 



