184 



Dr. Carpenter's Preliminary Report [Dec. 17, 



cable, p. 182) to the few forms that have been brought up by the Sounding- 

 apparatus*. 



I. The collective results of these recent Dredgings have conclusively 

 established the justice of the inference formerly drawn by Dr. Wallich from 

 the more restricted data he had collected, as to the existence of a varied and 

 abundant submarine Fauna, at depths which have been generally supposed 

 to be either altogether azoic, or occupied only by Animals of very low type. 

 And a complete disproof has thus been furnished of the doctrine, against 

 which Dr. Wallich argued with great force, that a certain amount of bathy- 

 metric pressure must be prejudicial, if not absolutely fatal, to higher forms 

 of Animal life. 



In much that has been put forward upon this subject, two important con- 

 siderations have been altogether ignored : — first, that pressure will not act 

 upon an Animal whose body entirely consists of solid and liquid parts, in 

 the same manner as it acts upon one that includes air-cavities ; and second, 

 that as fluids press equally in all directions, an Animal immersed at any 

 depth is just as free to move one part upon another, as it would be if living 

 near the surface. The right point from which to look at this subject has 

 long appeared to me to be the condition of a drop of water, conceived as 

 carried down from the surface to a depth (say) of 1100 fathoms [2012 

 metres], at which the pressure will be about 200 atmospheres, or 3000 lbs. 

 [1360 kilogr.] upon the square inch. Let it be conceived that this drop 

 is inclosed in a pellicle of the thinnest possible membrane, fitted only to 

 separate it from the surrounding medium, but having in itself no power of 

 resistance. Now it is obvious that this drop would maintain its form, 

 whatever this may have originally been, entirely unchanged, being neither 

 flattened-out into a plane, nor reduced to a sphere, by pressure to any 

 amount which acts upon it equally in all directions ; while its bulk will 

 only undergo reduction, under a pressure of 200 atmospheres, to the extent 

 of less than one-hundredth. Next, let us suppose, instead of a drop of 

 water contained within a pellicle, a particle of the semifluid "sarcode" of 

 which the body of a Ilhizopod is composed ; in which the more liquid 

 interior (endosarc) is contained by a more tenacious external layer (ecto- 

 sarc), the contractility of which gives rise to continual changes of form, 

 that are subservient to the movement of the creature from place to place, 

 and also to the ingestion of its food. Now, it will be obvious to any one 

 who follows out the law of fluid pressure in its application to an Animal of 

 this simple constitution, that so long as these changes of form do not 

 involve a change of bulk, pressure to any amount exerts no antagonizing 

 influence ; so that its movements can be performed with the same freedom 

 on the ocean-bottom as they can be near the surface. And, further, even 



* It is reported that the Swedish Expedition, which has recently returned from Spitz- 

 bergen, has brought up a considerable number and variety of animals from depths of 

 2000 fathoms and upwards ; but whether these were obtained by the Dredge or by the 

 ' Bulldogsmaskinen," I have not yet learned. 



