38 



PROBLEMS IN PHOTOSYNTHESIS 



thermophilic Chlorella is identical with that of common Chlorella, except that 

 the rate of photosynthesis is 10 times higher and the cell growth is 100 times 

 more rapid (6). Each cell produces 1000 cells within 24 hours. For these 

 reasons, thermophilic Chlorella may be of exceptional value in studying the 

 technical applications of photosynthesis, e.g., air purification in submarines 

 and space ships (6). 



§ 16 Principles of Manometry 



The manometric methods carefully developed by Warburg (21, 22) are 

 the methods of choice in measuring metabolic processes involving gases 

 (respiration, fermentations and photosynthesis). Measurements are made 

 either with a simple manometer (Fig. 16) or with the differential manometer 



,<^^ 



Fig. 16. Warburg's simple open-arm, 

 fixed-volume manometer. 



Fig. 17. The differential manometer 



(Fig. 17). The first differential manometer was constructed in 1900 by E. 

 Warburg (18) who used it for the measurement of ozonisation. It was im- 

 proved for physiological experiments by Barcroft (2) in 1908. Figure 17 

 shows the differential manometer used by Warburg and Negelein in their 

 experiments on photosynthesis. The simple manometer constructed by 

 Haldane and Barcroft (13) in 1902 for the study of blood gases is the most 

 suitable for physiological experiments. It has been improved by Warburg. 

 However, manometry itself was not new, as de Saussure had already made use 

 of it. The simple manometer is connected to the manometer vessel (Fig. 18) 



