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Puget Sound Marine Sta. Pub. 



Vol. 1, No. 23 



obtained when special precautions were taken to prevent loss of carbon 

 dioxide. These figures make it clear that carbon dioxide is present only 

 V ery occasionally and then in small, though unmistakable, quantities. 



Similar results were obtained by a more extended series of analyses in 

 which the gas was displaced by water saturated with gas from other speci- 

 mens which had been collected at the same place and time. Mention 

 should be made of one exceptional case in which an apparently healthy 

 kelp showed 1.2 per cent of carbon dioxide. 



That the carbon dioxide content did not vary with the time of day 

 is brought out in table 3. The occurrence of carbon dioxide, while seem- 

 ingly irregular, is of interest and will be investigated by more refined 

 methods than those of technical gas analysis. The presence of carbon 



/focA 

 PLATE 45 



monoxide is of much more striking interest due to its possible bearing on 

 the mechanism of photosynthesis. Table 3 gives a rather extended set of 

 measurements all made within 24 hours. The gas was collected (Plate 

 45) over sea water in glass jars which were sealed and then brought to the 



