LUCKAN: ABUTILON THEOPHRASTI. 225 



of elaioplasts in the growing apex of the stem and the absence of 

 them in the older stem seems to support PoUtis ' theory that they 

 are active only a short time and are then used up by the plant 

 tissues, but the fact that the elaioplasts are present in the cells of 

 the cortex of the old root is against this. 



In regard to their origin, I am not able positively to confirm 

 either theory. I find leucoplasts aggregated about the nucleus 

 in the cells of the soaked seed, but I could not find intermediate 

 steps, for it seems that in my material the elaioplasts do not form 

 oil until they have attained a spherical form and ultimate size. 

 Certainly the hairs of the Gaillardia studied by Beer are unusually 

 favorable subjects for showing the course of elaioplast develop- 

 ment. 



Politis found the elaioplasts usually present in the epidermis of 

 the floral organs, but their occurrence in other organs was incon- 

 stant. He says they are an active organ of the cell during growth. 

 When active the elaioplasts have a rotating motion in the cell; 

 when at rest the elaioplasts may assume various forms as a last 

 phase of development. He found elaioplasts present in the fol- 

 lowing species of Malvacecas : Hibiscus syraicus, Althea rosea, Maha 

 rotundifolia, M. sylvestris, Gossypiuni arhoreum, Gothea cauliflora. 



MICROCHEMISTRY OF CELL CONTENTS. 



The Leaf. 



Leaves that had been in bright sunlight, brought in and tested 

 for starch with iodine, showed the presence of starch. Similar 

 leaves boiled in Fehling's solution showed crystals of cuprous 

 oxide, indicating the presence of sugar in the form of monosac- 

 charide. 



Sections of leaves in Sudan III overnight showed palisade cells 

 orange yellow, but not good demonstration of oil. The large 

 glandular hairs showed droplets of bright orange red, indicating 

 oil. Leaf sections soaked in chloroform and then tested with 

 Sudan III did not give the red color reaction. 



Volatile oil tests were made by collecting the distillate from 

 leaf tissues on cover slips rinsed in chloroform, which were then 

 treated with Sudan III, and iodine fumies. On cover slips without 

 the distillate, but otherwise treated in the same way, no oil was 

 demonstrated; on those with the distillate, however, a good posi- 

 tive test was shown, indicating the presence of volatile oil in the 

 leaf. 



15— Sci. BuL X. 



