SEASONAL PHENOMENA IN THE LIFE OF PLANTS 457 



Plants intended for treatment with ether, such as flowering 

 shoots of Hlac and rhizomes of Uly of the valley, are placed in 

 airtight wooden boxes with closely 

 fitting doors; in these is also 

 placed a small amount of ethyl 

 ether. The concentration of ether 

 used is 0.5 cc. per liter of air. 

 The plants are allowed to stand 

 in this vapor for 24 or 48 hr., 

 after which they are transferred 

 to a warm greenhouse. Soon the 

 treated plants will open their buds 

 and begin to bloom, while the 

 controls, though receiving an 

 identical treatment except for be- 

 ing subjected to the action of ether, will remain dormant (Fig 

 141). 



Fig. 142. — A tank for warm baths, 

 heated from below by a radiator, 

 r, and covered with felt, s {after 

 Molisch) . 



Fig. 143. — Shoot of lilac. Right branch subjected to a warm bath, left one 



remained untreated {after Duggar). 



Exposure to a warm bath is still simpler. The aerial parts 

 of the plants are immersed for 9 to 12 hr. in water at 30 to 35°C. 



