CAUSES OF DEPLETION. 



i namely ^all the smaller streams form the sewers of the ad- 

 jacent country, and fall into the larger rivers, and the latter 

 again act as the sewers of the towns and of the kingdom, and 

 are carriers of their congregated impurities finally to the sea. 

 The increasing population of human beings charges the 

 rivers every day with more and more foul matters, the re- 

 fuse of towns and the agrarian districts 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 introduced, 

 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 condition 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 pedicle or neck of the egg, hermetically 



