Mar. i, 1921 Utilization of Cotyledons of Bean Seedlings 877 



they were washed with sterile, distilled water and germinated between 

 blotting papers which had been treated with hydrochloric acid and washed 

 free from chlorids with distilled water. The germinating dish was of 

 porcelain and was sterilized by heating at 180 C. for two hours. The 

 beans were allowed to germinate until the radicles were 1 cm. in length, 

 when the integuments were removed and the radicles wrapped in sterile 

 absorbent cotton which had previously been treated with hydrochloric 

 acid and washed free from chlorids with distilled water. This cotton 

 gave practically no ash when incinerated. After the radicles had been 

 wrapped in the absorbent cotton, each bean thus prepared was placed 

 in the mouth of a test tube which had been thoroughly coated inside with 

 paraffin and was held there by applying a few drops of melted paraffin. 

 The test tubes were thoroughly washed with distilled water before the 

 distilled water in which the seedlings grew was placed in them. This 

 water was replaced as rapidly as it was removed by evaporation and by 

 transpiration. The bean seedlings were allowed to grow until they had 

 etiolated and wilted. The seedlings thus formed were uniform in size 

 and development, being about 7 inches in height, with a well-developed 

 root system and having two perfectly formed leaves which were somewhat 

 undersized. The etiolation of the leaves and cessation of growth was 

 taken as a point of maturity at which the cotyledons were removed, in 

 a brown and greatly shriveled condition. They were analyzed as already 

 described, and the results are presented in Table I. Inasmuch as a new 

 lot of Kentucky Wonder beans was used for this part of the experiment, 

 200 normal cotyledons from beans of this lot were analyzed and the results 

 included in the table for comparison. 



