1909.] NATURAL SCIENCES OF PHILADELPHIA. 61 



of water; five drops of chemically pure nitric acid in fifty cubic centi- 

 meters of water; three bottles contained filtered water. 



Hydrochloric Acid. — March 11: Buds not burst, but resin abundant 

 and more fluid. March 15, March 18, March 20: No change reported 

 in the record of this branch. March 25 : Bud burst at tip. March 28 : 

 Bud nearly fully burst, leaves still tightly folded. April 1, April 5: 

 No change. April 13 : Twig dead. 



Filtered Water (A). — March 11 : Terminal bud very resinous. March 

 15: Terminal buds well expanded. March 18: Large buds well ex- 

 panded, but leaves still tightly folded. March 20 : Terminal buds with 

 leaves still erect. March 25: Leaves of terminal bud distinct and 

 horizontal, but segments still folded together, covered with rusty 

 hairs. March 28: Leaflets beginning to separate. April 1, April 5: 

 No advance. April 13: Twig dead. 



(B) No response on March 8 and March 11. March 15: One lateral 

 bud with woolly leaves showing. March 18: Leaves of two lateral 

 buds flattened out horizontally. March 20: All of the leaves of the 

 lateral buds placed horizontally. March 25: Leaves began to lose 

 their tomentum. March 28: Leaflets began to separate. April 1, 

 April 5: No change. April 13: Twig dead. 



(C) March 11: Buds became sticky, resinous, inner scales began to 

 show between the outer scales. March 15: Buds well expanded, but 

 not fully burst. March 18: Buds burst, young leaves still folded 

 together. March 20 : Bud fully open, one leaf horizontal. March 25 : 

 Leaves all horizontal, covered with tomentum. March 28: Leaflets 

 still folded together. April 1 : Leaves somewhat withered. 



Populus monilifera. — The following chemical solutions were 

 used in experimenting with the twigs of the Carolina poplar: Chromic 

 acid, one per cent.; filtered water; five decigrams of sodium bicarbo- 

 nate in fifty cubic centimeters of water; five decigrams of sodium 

 chloride in fifty cubic centimeters of water; five drops of chemically 

 pure sulphuric acid in 100 cubic centimeters of water; ten drops of 

 chemically pure hydrochloric acid in fifty cubic centimeters of water; 

 twenty drops of chemically pure sulphuric acid in 100 cubic centi- 

 meters of water; menthol water; filtered tap water; 100 cubic centi- 

 meters of ether in 500 cubic centimeters of water; 200 cubic centi- 

 meters chemically pure ammonium hydrate in 1 ,000 cubic centimeters 

 of water; two grams of ammonium sulphate in 600 cubic centimeters 

 of water; saturated corrosive sublimate solution diluted in 1,000 cubic 

 centimeters of water. 



