BULLETIN OF THE UNITED STATES FISH COMMISSION. 259 



flesh, which had begun to putrefy, has gone into the stomachs of num- 

 berless crustaceans, and is, in part at least, to be transformed into live, 

 healthy flesh. 



IV. — WlIAT WAS THOUGHT IN FORMER TIMES OF THE IIAEITABLE- 



NESS OF THE DEEP. 



Ought we not, iu our discourse, to make a difference between the sur- 

 face of the sea and its depths ? " It may be," some one will say, " that 

 life is richer in the sea than on land; this may apply not only to the 

 shallow waters near the coast, but also to the surface of the open sea ; 

 but in the great depths life cannot exist, or at least it cannot be varied 

 iu form and number. Physics teach us that an animal thrown into the 

 water must bear the weight of the entire quantity of water which rests 

 upon it. For this reason the pressure, at a depth of 500 meters, is 50 

 kilograms per square centimeter. Is it possible that any living being 

 can stand such a pressure without being crushed ? And what is 500 

 meters compared with the immeasurable depth of the ocean ! Depths 

 of 3,000 and 4,000 meters are common, and there are even some of 8,000 

 and more meters. 



tl It is true that light will penetrate the water, but not without losing 

 some of its strength ; and one generally calculates that a layer of water 

 100 meters thick is sufficient to entirely intercept the light. The sun- 

 shine, therefore, only acts on the surface of the sea, and a short distance 

 below the surface everything is shrouded iu impenetrable gloom. In 

 that dark abyss no plants can grow and no animals can live; in its 

 depths the ocean is nothing but an unmeasured, dark, and dead desert." 



Thus scientists talked hardly five and twenty years ago, and this 

 idea was then very generally entertained. Experience had not taught 

 this, for scientists had not descended into this dark abyss with a Ian- 

 tern to examine it. They had not gone to sea and let down nets into 

 the depths for the purpose of seeing what they would bring to light; for 

 in those days suitable instruments for making such observations were 

 unknown. 



Little more had been done than to sound a few depths with a lead 

 weight covered with glue, so that objects at the bottom of the sea 

 might stick to it, and thus be brought to light. This way of sounding 

 was moreover so tedious a work that it was but rarely undertaken. 

 The plummet must be tolerably heavy, for otherwise the current will 

 not allow it and its interminable line to reach the depths. To let the 

 plummet down was easy enough, but to haul it up again was a labor at 

 which even sailors could easily work themselves weary. 



No, it was assuredly not from experience that scientists derived their 

 idea that the depths of the sea were a dark desert ; they only reasoned 

 so from speculations, to engage in which they need not leave their com- 

 fortable studies. In our time it has been shown how deceptive such 

 speculations may be, and how necessary it is to examine nature herself, 



