' 





iQ2o] LANGDON & GAI LEY— CARBON MONOXIDE 231 



of the mechanisms of photosynthesis, carbon monoxide has often 

 been considered as an intermediate step in the reduction of carbon 

 J dioxide, especially since it is so closely related chemically to 



formaldehyde and formic acid. Heretofore there has never been 

 any evidence of the existence of free carbon monoxide within a 

 living plant. The possibility of its formation by enzyme action or 

 by decay processes was early suggested, and was the first point 

 investigated. Finely ground kelp was allowed to undergo autolysis 

 in contact with sea water, and the gases evolved were examined. 

 No carbon monoxide was formed, but the gas consisted almost 

 entirely of carbon dioxide and hydrogen. 



The next step was to determine how rapidly carbon monoxide 

 was formed within the living plant. The method of work and the 

 further discussion will be made more clear if prefaced by a brief 

 - description of Nereocystis. Fig. 1 shows the kelp as it lies normally, 

 almost submerged in the sea water, anchored to the rock bottom 

 and supporting the streaming fronds from the top of the hollow 

 gas-filled stipe. The plants vary greatly in size. Individuals are 

 often 80-100 ft. in length, and contain several liters of gas which 

 is usually at reduced pressures. 3 The inside of the gas cavity is 

 relatively dry, and is lined with a delicate weblike structure called 

 sieve tubes. The plant will withstand a great deal of mutilation 

 and still continue to live and grow, if kept in sea water. 4 



It was found practicable to cut off the lower part of the stipe 

 and in the upper part to substitute a gas of known composition 

 for that normally present in the pneumatocyst. The cut end was 

 closed by a cork stopper, and the plant weighted and submerged 

 in the sea, tied to a floating support, as shown in fig. 2. After a 

 suitable interval, changes in the gas composition were determined 

 by analysis. In the first experiments tried, primarily to deter- 

 mine the rate of formation of carbon monoxide, air was substituted 

 for the kelp gas. This was accomplished by filling the cut stipe 

 with sea water and then emptying. This process repeated three 

 or four times removed the small bubbles that tended to adhere to 

 the delicate sieve tube lining of the pneumatocyst, and insured the 



^ Frye, T. C, Puget Sound Marine Sta. Publ. 1:85. 1916. 

 4 Fallis, A., Puget Sound Marine Sta. Publ. 1:1. 1916. 



