SEA-FISHERIES LABORATORY. 239 



fact that the above views were expressed in the Proceedings 

 of the Royal Society nearly ten years ago, and that shortly 

 thereafter the " Buffer " effect in the plasma was not only 

 recognised, but estimated by Moore and Wilson, and published 

 in 1906 in the first volume of the Bio-chemical Journal. 



The following tabulated statement gives a record of the 

 titration to phenol-phthalein and to methyl-orange of the 

 sea-water freshly drawn in the neighbourhood of Port Erin, 

 Isle of Man, and in the Irish Sea, at various seasonal periods 

 during the years 1912-14. 



The titrations were made by adding four drops of 0-5 per 

 cent, solution of phenol-phthalein (by measure about 0-13 c.c.) 

 to 100 c.c. of the sea-water, and then titrating with N/100 

 hydrochloric acid till the pink colour was just on the point of 

 disappearing. 



Two points are noteworthy, first that throughout the long 

 series of observations the fresh sea-water was invariably 

 alkaline to phenol-phthalein indicating a value of hydrogen-ion 

 concentration lying above P H> 10 ~ 8 , or considerably higher than 

 the values obtained by other recent observers such as Sorensen 

 and Palitzsch 3 - 4 in sea-water from other regions, and, secondly, 

 that there is a seasonal variation, the hydrogen-ion concentra- 

 tion being higher in winter, and decreasing in spring and 

 summer. Although the latter variation is small, the differences 

 in the amount of acid required to reduce the level to the neutral 

 point of the phenol-phthalein indicator show, when applied to 

 the vast volumes of sea-water affected, great photo-synthetic 

 activities of plants, and corresponding animal activities in 

 oxidation. The results indicate a great crop, or annual 

 variation in the water, corresponding to the seasonal variations 

 on the land in the round of the year. The photo-synthetic 

 crops in the sea-water, reckoned as carbohydrate produced, are 

 similar to those on a land surface, and amount to several tons 

 of carbohydrate per acre ; this then forms the food for the 

 floating animal-life of the sea. 

 Q 



