CARBON MONOXIDE 105 



thus forms a reserve of carbon which is converted into carbon 

 dioxide, available for carbon assimilation, by the decomposi- 

 tion of the acids when photosynthetic conditions supervene. 

 Comparable phenomena occur in bacteria in certain conditions, 

 the formation of acids being a well-known occurrence in their 

 oxidative activities. 



Of other products of respiration, carbon monoxide has been 

 described by Langdon and Gailey in the pneumatocysts of 

 Nereocystis Luetkeana* a unique example as far as is known. 

 The bladders contain a mixture of nitrogen, oxygen, car- 

 bon monoxide, but no carbon dioxide. An analysis of the 

 gaseous contents of over a thousand of these floats showed the 

 carbon monoxide to vary from 1 to 12 per cent, by volume, 

 whilst the oxygen ranged from 15 to 25 per cent. Only when 

 oxygen is present does carbon monoxide form in the bladders ; 

 if the oxygen be replaced by nitrogen or hydrogen, no carbon 

 monoxide results. The gas is produced naturally both by day 

 and by night but it is not formed when the plant is ground 

 and allowed to undergo autolysis or decay, in which circum- 

 stances carbon dioxide and hydrogen are produced. From 

 these facts it is concluded that the gas is a respiratory product 

 and has no connection with carbon assimilation. 



In further illustration of the respiration of fats, the work 

 of Stephenson and Whetham f on the Timothy grass baccillus, 

 which is characterized by a high fat content, may be mentioned. 

 It was cultivated at 57 on a medium containing ammonium 

 phosphate as the sole source of nitrogen, and glucose as the 

 only source of carbon, the pW being maintained at 8-0. The 

 periodic analyses of the proteins and fats of the plants and 

 analyses of the medium showed that the sugar was completely 

 used in about three weeks, during which period the amounts 

 of fat and protein synthesized gradually increased to a maxi- 

 mum until no sugar remained in the culture medium. Then 

 the amount of fat contained in the organism rapidly decreased, 



♦Langdon: " Journ. Amer. Chem. Soc," 1917. 39. M9- Langdon 

 and Gailey : " Bot. Gaz.," 1920, 70, 230. 



f Stephenson and Whetham : " Proc. Roy. Soc," B, 1922, 93, 262 ; 

 1923. 95. 200. 



