1916 Langdonj on Carbon Monoxide 243 



laboratory for analysis. The samples were in all cases collected from 

 large specimens of kelp from the same location and as nearly uniform in 

 appearance and size as possible. Column 2, table S, gives the pressures 

 of the gases taken just before collection. The figures show such irreg- 

 ularity that there is no evident relation between pressure and chemical 

 composition of the gas. Also for samples collected at the same hour of the 

 day there is great variation in the percentage composition. For example, 

 in the six samples collected at 8 A. ]\I. the range of carbon monoxide con- 

 tent was from 1.2 to 8.6 per cent, and the oxygen range from 16.4 to 22.9 

 per cent. The existence of such great variation between individuals would 

 necessitate the analysis of an enormous number of samples in order to 

 obtain average values, which would indicate whether the composition of the 

 gas varies with the time of day, that is, with the light intensity. The rate 

 of flow of water past the plant may have some bearing on the composition 

 of the gas, and it appears to be true that the highest carbon monoxide 

 content is to be found in those larger and more healthy kelps which grow 

 where the tidal currents are the swiftest. The mature kelps have a higher 

 carbon monoxide content than do the young ones. 



It has not been determined whether or not the carbon monoxide gas 

 functions actively in the metabolic processes of the plant, whether it is an 

 accumulated waste product or is formed by processes of decay. Work 

 is now under way which it is hoped will answer these questions. No 

 hypothesis is offered by the author, as yet, to account for its presence in 

 the pneumatocyst of Nereocystis, but the purpose of this paper is simply 

 to give what has heretofore been lacking, namely, experimental evidence 

 of the actual existence of free carbon monoxide in a living plant. 



For those not familiar with the plant in which CO was found, the fol- 

 lowing brief description is given : 



The kelp Nereocystis luetkeana is a brown alga thriving only on the 

 Pacific Coast. Its general external appearance is indicated in B of plate 

 45. The stipe is hollow from the bulb-like top to within a short -dis- 

 tance of the holdfast. The walls of the stipe are from a quarter to three- 

 quarters of an inch in thickness and are lined with a delicate web-like 

 structure which is relatively quite dry. The hollow space, in large speci- 

 mens, has a capacity of from three to four liters. The gas is almost al- 

 ways under less than atmospheric pressure. Frye (3) reports an average of 

 77 mm. of mercury below normal air pressure. The full-grown kelps vary 

 greatly in length. The author has worked with specimens as long as 85 

 feet, but much longer ones have been reported. Most of this enormous 

 growth takes place in the short period of 10-15 weeks. The largest and 

 liealthiest kelps grow where the current flows the strongest and where there 

 is consequently the most chance for the great surfaces of the fronds to 



