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THE AUSTRALIAN MUSEUM MAGAZINE. 



but when it was alive, under the pres- 

 sure from which it was so suddenly re- 

 leased, its tissues may have been as 

 firm and dense as a piece of rope. 

 Tliese deep-water fishes are liable to a 

 strange and paradoxical fate ; they 

 alone of all things in the world may 

 come to their death 1jy tuml)ling up- 

 wards. By expansion and contraction 

 of their swim bladder, fish control their 

 movements and balance. If an abyssal 

 fish should chance to mount too high 

 in pursuit of game, the swim bladder 

 may expand beyond control of the mus- 

 cles; then its fate is sealed, for the 

 helpless creature, swollen to bursting, 

 is carried liigher and higher, even 

 through miles of water, to the surface. 



A TUh that has Fuffercd "decompression." 

 After being drawn suddenly from a great depth 

 to the surface, tlie body was burst by release 

 of pressure, so that the entrails protrude from 

 the mouth, the eyes start out from the head, 

 and the belly is much distended. 

 From Perricr's ''Lfs Explorations sous marins." 



The first of the deep-sea fauna seen by 

 naturalists consisted of such decom- 

 pressed fish found stranded on the 

 beach or floating on the surface. 



It is pressure that makes diving so 

 dangerous an occupation. Some of the 

 smartest of the South Sea Islanders 

 are said to swim down for seventy or 

 eighty feet, and diving in a dress with 

 an air pump has with great care been 

 successfully accomjalished down to two 

 hundred feet. But the divers who, 

 tempt<'d by great reward, venture much 

 past a depth of 20 fathoms are liable 

 to be pulled up in a paralysed condi- 

 tion. The danger lies not in the de- 

 scent, as would be anticipated, but in 

 the ascent. In the familiar soda-water 

 siphon, the water has ])een charged l)y 



forcing gas into it under pressure; 

 when the soda water is poured out, the 

 gas, being suddenly released from pres- 

 sure, effervesces violently. In a similar 

 way when a diver descends, gases 

 from the air he breathes, at a pressure 

 corresponding to the dejitli reached, 

 are forced into liis blood. When he 

 ascends, the pressure diminishes, and 

 the released gases tend to effervesce 

 as in the case of the soda-water dis- 

 charged from the siphon ; should a bub- 

 })le thus burst from the blood into the 

 brain or spinal cord, paralysis at once 

 occurs. Practical divers treat paralysis 

 by rejiacking the sufferer in his dress, 

 lowering him to Ins former depth, hop- 

 ing thus to reduce the bubbles, and 

 drawing him up again very gradually. 

 A prudent diver ascends from great 

 depths slowly and rests at various 

 stages. 



It is considered, but this is a point 

 not yet decided, that the animals of the 

 sea live either al)out the surface, or on 

 and near the l)ottom, and tliat the in- 

 termediate sjiace, which may be miles 

 deep, is alnidst ])arren of life. The 

 pelagic fauna i-; that which floats at, or 

 near the surface, and is totally different 

 from either that which lives on the sea 

 floor, or that which inhabits the beach. 

 A glance over the ocean from the deck 

 of a ship might convev the imj^ression 

 that the sea is indeed the "waste of 

 waters" that it has been called, that, 

 but for an occasional albatross or por- 

 poise, it is a lifeless desert. But the 

 presence of such voracious animals as 

 ]")orpoises and albatrosses are indica- 

 tions of an ample food supply. Though 

 myriads of animals are always afloat on 

 the surface of the sea, tliev fail to 

 catch the eye of the traveller, for, 

 either tliey are \ery small, or trans- 

 parent, or disguised by their blue col- 

 our. In rain or hot sunshine some of 

 the pelagic fauna may sink a little dis- 

 tance for shelter beneath the surfac^e. 



But after dark no one would make 

 the mistake of calling the sea lifeless. 

 An approach by night to a big city is 

 marked by tlie ajjpearance of a long 

 array of lights; since each individual 

 light is evidence of the care of a human 

 hand, every sparkle in the dark repre- 

 sents a life. Had some pestilence sud- 



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