148 Proceedings of Indiana Acad c in 1/ of ^icivnce. 



of the miaired plant. This was luade iiecessary by the greater transpiration 

 and j^rowtli activities of tlie plant whic-h was aired in the way mentioned. 

 The air used to aerate the specimen of Avena sativa as well as the others 

 mentioned in this paper was propelled by the Keknle apparatus. 



In like manner air was passed through a Sachs culture solution in which 

 were growing seedlings of Brassica alba. Here again the aired specimen 

 showed a great advance over the unaired plant. When the plants were two 

 weeks old the aired specimen was 12 cm. high, while the unaired specimen 

 was 5 cm., high. The roots of the unaired specimen were rather few and 

 long, while those of the aired specimen Avere aggregated more into a mass 

 of considerable size, were much denser and more numerous and the total 

 length many times greater. The aerial porticm of the aired plant was not 

 only taller but more than twice as broad. The leaves of the aired plant 

 were much larger and broader and more numerous and the transpiratory 

 activity as in Avena sativa was much increased. The comparative difference 

 in size of the aired and unaired specimens of Brassica alba was a little 

 greater as the measurements will show, than the difference in size of the 

 Avena sativa plants. The dried weight of the aired specimen of Brassica 

 alba was 110 mg. while that of the unaired specimen was 25 mg. 



Seedlings of Pisum sativum were grown in a Sachs nutrient solution as 

 the above mentioned specimens some of which were aired and some not 

 aired. Here again the aired specimen grew fastest and best. When twenty 

 days old the aired seedlings were 85 cm. high and the non-aired 41 cm. high. 

 The dry weight of the aired plant was 2.5 grs. while that of the unaired 

 plant was 0.5 gr. In this experiment the aired specimen was nearly twice 

 the height of the unaired plant while the dry weight exceeded that of the 

 unaired five times. 



Other experiments on Fagopyrum esculentum and on Helianthus annuus 

 gave similar differences. The plants of Fagopyrum esculentum especially 

 showed decided differences. Those specimens that were aired formed flow- 

 ers profusely two weeks sooner than the specimens which had not been 

 aired. 



In addition to the above experiments which Is only an outline of part of 

 the work done. Miss E. G. James is at present working on an extended 

 series of experiments on aeration of plants under my direction. She has 

 invented several new and necessary pieces of apparatus for carrying out 

 the work under different conditions. Experiments performed by her on 

 Lactuca sativa confirm my exi^eriments and also extend them in various 

 ways. 



