PAPERS ON BIOLOGY AND AGRICULTLRE 113 



Density 3, seeds which sank in a solution of 1.22 sp. gr. ; 

 (range from 1.27— through 1.22) ; 



Density 4, seeds which sank in a solution of 1.17 sp. gr. ; 

 (range from 1.22— through 1.17) ; 



Density 5, seeds which sank in a solution of 1.12 sp. gr. ; 

 (range from 1.17-through 1.12) ; 



Density 6. seeds which floated in a solution of 1.12 sp. gr. 

 By this method the seeds were exposed to the solution but a 

 few seconds and, as germination and growth tests showed, 

 suffered no harm from the process. 



The seeds passed through the successive solutions varied 

 in length from 8.3 mm. to 18.5 mm. These were di\ided into 

 three groups of the following respective lengths : 



Large seeds, range in millimeters from 18.5 to 15.1; 

 medium seeds, range in millimeters from 15.1 to 11.7 ; small 

 seeds, range in millimeters from 11.7 to 8.3. 



(2) Treatment of Seedlings. 



Twenty-four seeds of each gi'oup were individually 

 weighed and measured. Twelve were placed in beakers of 

 sphagnum, the others were planted, one quarter of an inch 

 below the surface of the soil, in small flower pots. In put- 

 ting the seeds to geiTninate, the micropyle end was always 

 placed down thereby avoiding unnecessary curving of the 

 seedling. The beakers and the pots were kept in covered 

 metal cases at a temperature of 20 -C during germination. 

 When the seedlings in the sphagnum started to put forth 

 secondary roots they were transferred to small aspirator 

 bottles filled with tap water. This water is essentially a 

 nutrient solution as the chemical analysis given by the Illi- 

 nois State Water Sur\'ey (8) shows. The seedlings were 

 held in place by means of fine aluminum wire and by a sup- 

 port which was fastened to the neck of the bottle. The bot- 

 tles were then placed into the cases where they were left 

 until the seedlings were ready for use. The water in the 

 bottles was renewed on alternate days. 



When the seedlings were one or two centimeters in 

 height, the pots or bottles were placed into rectangular 

 metal cases consisting of a lower part fifteen centimeters in 



