43 



actions between the various bissues, and the blood or lymph which 

 constitutes what has been named the internal environment. 



Mirine Bacteriology covers all the activities of Bacteria in 

 the sea, 



1. Oceanic Biology 



This heading covers much the san.e fields as does 

 Terrestrial Biology; but there are several very good reasons for 

 studying the oceanic phases of Biology as distinct from the 

 terrestrial. There is, to begin with, ample justification fro..i^the 

 empiric standpoint, namely to complete our knov/ledge of the Icinds 

 of animals and plants that exist on this planet, for many of the 

 inhabitants of the sea (i.e., of 2/3 of the earth's surface) are 

 still unhnown, while our hnowledge of many others is still far from 

 complete, even as to their structures, let alone their activities. 

 Collecting expeditions, at sea, are therefore still needed, es- 

 pecially along the less frequented coasts, and in the mid and 

 abyssal- depths of the ocean basins, hand in hand with which mu:^t 

 go the study, in Huseums ashore, of the collections so gather 3d. In 

 this way fishes, crustaceans, molluscs, etc., never before seen, 

 are constantly being brought to light. 



Oceanic Biology also has a very important and direct economic 

 bearing, discussed in another chapter of this report (Page 67 ). 



We find, however, another reason stronger than either of these 

 for devoting special attention to the plant and animal communities 

 of the oceans, in the fact that the peculiarities of the oceanic 

 environxT.ent make it possible to study the basic relationship botr-een 

 the marine organism and its physical surroundings, and between 

 different species or groups of anim.als and plants, in a more direct 

 way in the sea than can be done on the land. The sea is, therefore, 

 in many respects the most favorable natural laboratory for investi- 

 gations into the laws that govern animal and plant economy. 



The pecu].iarities of the sea that m.ake this true ara: (1) the 

 simplicity of the marine environment as contrasted with the 

 terrestrial; (3) its comparative constancy and uniformity in tirae 

 as well as in space; and (3) the fact that the v/aters of the sea, 

 as contrasted with the air, are em.phatically a favorable environ- 

 ment, not only from the cbemical standpoint (discussed under 

 Physiology, Page 56 ), "but also from the physical-mechanical. 



The first and aost obvious physical advantaj^e of rea ?/atar rs 

 an environment is that it is not dry, lika the air, but is an aqueous 

 solution. The bearing of this fact is simple. On land every 

 animal or plant must either develop some protection to prevent its 

 vital substance from drying up, or its habitat must be restricter' 

 to places that are permanently damp. The basic value of the barh, 

 of the rind, or of the impervious shells or shins of one kind or 

 another, de^.'eloped by terrestrial plants and animals, is not so 

 much to protect against mechanical damage (although this secondary 

 purpose must also be served), but to guard against the constant 

 danger of drying up. Consider, for example, the fate of an earth- 

 worm, with its pervious shin, when caught out in the sun on the 



