1916 



Shelfordj on Physiological Differences 



161 



Table 1. The dissolved gases 

 ers) (24) 



of the sea icater {from Shelf ord and Pore- 

 J data in cc. per liter. 



It is a matter of some surprise to find that there is a constant differ- 

 ence in the water of the two sides of the harbor on which the station is 

 located (compare lines 5, 6 and 7 with 8, 9 and 10). The south side 

 is rocky at the point where the station is situated. Opposite it there is a 

 sandy and gravelly bottomed shallow area with eel grass and much Ulva. 

 The water on the south side is more acid at all times than the water on 

 the north side. The water on the north side is usually neutral or slightly 

 alkaline. At times, especially at the end of a sunny day, it is decidedly 

 alkaline. The station being located on the rocky acid side has supplied 

 water pumped usually in the evening and early morning and has never been 

 satisfactory on account of the fact that animals do not develop well in 

 acid water (14). Thus the eggs of most animals die in the tank water; 

 this can easily be remedied by extending the intake pipe across the harbor. 



The oxygen content of the water is higher on the north side of the 

 harbor where there is an abundance of vegetation. It is often nearly 

 twice saturation in this vegetation. On the south side of the harbor the 

 oxygen content rarely reaches saturation. The sewage from the town of 

 Friday Harbor and houses adjacent to the shore no doubt renders the 

 water along the shore in front of the station more acid and reduces the 

 oxygen content, biiJ; this influence can not be very pronounced on account 

 of the continued stirring of the water by tide movement. 



In addition to this, a series of oxygen determinations were made 

 from which samples were collected by Miss lone Trees in the eel grass 

 across the harbor in front of the station over a little deeper water than 



