238 BOTANICAL GAZETTE [September 



by the technical gas analytical methods used in this work may be 

 playing important roles in plant processes. 



The gas contained in the hollow cavities of several other grow- 

 ing plants was investigated, but in no case was carbon monoxide 

 found. The gas obtained from a vigorously growing garden 

 pumpkin contained 18 per cent of oxygen with no carbon dioxide ^ 



or carbon monoxide. Very similar results were obtained from the 

 gas contained in the hollow stems of a species of Equisetum, the 



stem 



m 



In the original paper it was reported that there was no carbon 



monoxide in the gas obtained from the vesicles of Egregia Men- 

 ziesii, or in that obtained from Fucus evanescens. 



The Scripps Institute collected gas for the author from two of 

 the southern algae. One of these, Macrocystis pyrifera, showed no 

 carbon monoxide; while the other, Pelagophycus Porra, showed a 

 small carbon monoxide content. These gases were collected in 

 quart fruit jjars and shipped from La Jolla, California, to Seattle, 

 Washington, for analysis. To be definitely certain of the presence 

 of carbon monoxide in the gas from the elk kelp, Pelagophycus 

 Porra, it would be necessary to examine the freshly collected gas. 

 It is interesting to note that Pelagophycus Porra is very closely 

 related to Nereocystis Luetkeana, and is very similar in structure, 

 the inside of the gas cavity of both being characterized by the 

 presence of a pith web. 



The occurrence of free carbon monoxide within a living plant 

 is unique, so far as the authors have been able to ascertain. Its 

 further study in relation to plant life should prove interesting, and 

 it is not without a measure of regret that the authors leave this 

 field to other investigators. 



Summary 



1. The existence of a percentage of carbon monoxide in the gas 

 contained in the pneumatocyst of the Pacific Coast kelp Nereocystis 

 Luetkeana is confirmed. 



2. The substance of the kelp when ground and allowed to 

 undergo autolysis and decay does not form carbon monoxide by 

 enzyme action or fermentation process. 



