52 



which many si^rnif icant matters miq-ht be approached, if it could be 

 made feasible to control the.n in the Istoratory. 



FhysiolOR'y, furthermore, is concerned, not only with the 

 activities of individual forms, both as such, and as they illuminate 

 specific problems, tut also with the inter-connected activities of 

 different organic groups. The sea offers the readiest subjects for 

 such investigations, and those likely to provide results of the 

 widest significance. 



The most impelling lodestone to draw physiolo'2'ists to the sea is, 

 however, the physical and chemical nature of the salt-water environ- 

 ment. This aspect of the case has often b'^en emphasized of late,^ 



^3ee especially j. H. Henderson. "The Fitne s s of the Environment" . 



Te need m^^-rely point out that, protoplasm being organized as it 

 actually is, seb water is as nearly p-rfect a medium for it we can 

 conceive of. In fact, it is this very fitness alone that makes life 

 possible anywhere in th^ sea outside as well as inside a very narrow 

 coastal strip, for were sea water not nearly as heavy as protoplasm 

 (thus making flotation easy) and did it not carry in solution a 

 variety of chemical compounds usable by plants as food, the abundant 

 plant life of the s-as could not exist at all except close to the 

 lands. Without plants thrre could be no animals there, so that the 

 whole oceanic basin would be a desert. 



Marine Physiology, therefore, centers around sea water as an 

 environment for life, and, as has bi-en pointed out by others, sea 

 water is a fluid of quite special inter-st, both oecause it is the 

 commonest substance in the world, and because it so closely resembles 

 protoplasm and Mood plasm, minus their organic constituents. This 

 ■^'ntails studies of the sea water itself, because our knowledge of its 

 physical and chemical conditions is still incomplete, and our know- 

 ledge of it as a system v-^ry meagre. A.nd it is upon the picture of 

 the major cyclic changes there occurring, as a background that the 

 physiologist must diagram, in quantitative terms, the rhythmic 

 changes of significant ch^-mical constituents, before he can consid-r 

 the part that organisms of various types play in the ocean-equilibrium. 

 From the physiological standpoint, we only now begin to understand 

 the progressions of nutritive substances ynd the resulation of their 

 level of concentration, as related to depth, to distance from land, 

 to season&l periodicities etc. 



The marine environm'^nt also offers very practical advantages for 

 physiology, because of affording the most convenient working condi- 

 tions, depending upon avail'ibility of a wide variety of orer-anisms 

 throughout the year, which is a primary requirement. 



As a final thought on a somewhat different plan, contributed by 

 a leading physiologist, we may point out that one of the present 

 duties of physiology is the revivification and modernization of 

 general natural history. Long experience with fragmentary investie-a- 

 tions of the sea has at least made it clear that this association of 

 interests is desirable, and that life in the sea is one of its most 

 fruitful fields. Perhaps this is due to the fact that a certain men- 

 tal hiamility often follows contact vvith the ocean, its complexity and 

 its immensity. 



