402 Plant as an Index of Smoke Pollution 



District 

 Sutton 



Weetwood Lane 

 University 

 Hunslet 



The relative lipase activity in the oat grain grown in 1915 in the 

 districts mentioned was measured by allowing the enzymes present in 

 the grain to hydrolise an ethereal salt like ethyl butyrate or ethyl 

 acetate and observing the amounts of acid liberated by titration against 

 2V/10 NaOH. The results show that the activity of this enzyme as well 

 as that of the others previously mentioned is inhibited by smoke pollu- 

 tion. 



Effect of Smoke Pollution on Activity of Lipase in Oat Grain. 



In conclusion, I should like to express my indebtedness to Professor 

 Crowther and Professor Cohen for invaluable help and guidance all 

 through the investigations; to Mr Hector for assistance given in the 

 microscopic examination of many of the leaves; to Mr Frank for help 

 given in the measurements of the tints of the flowers; to Professor 

 Priestley for guidance in the estimation of enzyme activities ; and to all 

 those gentlemen who have so kindly placed their gardens at my disposal 

 for so many years. 



EXPLANATION OF PLATES XXIV, XXV 



Fig. 1. Oats from same sample of seed grown in different districts in and round Leeds, Adel, 



three miles to north of Leeds, Hunslet, Industrial Leeds. 

 Fig. 2. Sycamore. 

 Fig. 3. Lime. 

 Fig. 4. Ribes. Smoke-damaged leaves collected 29 May, 1914; from Woodhouse Moor, one 



mile to the north of Leeds. 

 Fig. 5. Holly leaf obtained from tree growing in industrial Leeds. (Upper half cleaned: 



lower half showing deposit of soot.) 

 Fig. 6. Leaves of Conifers, collected at Garforth, showing "sunk stomata" choked with 



tar. 

 Fig. 7. Section of Scotch fir, grown at Broxburn, showing damage done by fumes from 



Roman Camp Shale Works. 



