376 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



contained in the gastric juice of animals. The excessively 

 minute quantities of nitrogenous substance which cause in- 

 flection of a gland of Drosera are very astonishing in the 

 case of carbonate of ammonia about a twenty millionth of a 

 grain. 



INFLUENCE OF AMMONIA ON THE COLORS OF FLOWERS. 



The Journal of the Central Horticultural Society of France 

 gives some interesting details of the alterations which the 

 natural colors of flowers are subjected to under the influence 

 of ammonia. If we expose flowers originally of a violet hue 

 to the fumes disengaged by a cigar, we see these flowers 

 take a green tint more pronounced than was their proper 

 color. This change is due to the ammonia in the tobacco 

 smoke. Starting with this idea, the Italian Professor Gab- 

 ben has made a series of experiments having in view the 

 changes that ammonia brings about in the colors of different 

 flowers. He simply made use of a plate containing a cer- 

 tain quantity of a solution of ammonia known commonly as 

 volatile alkali. He shows that, under the influence of am- 

 monia, blue, violet, and purple flowers become a beautiful 

 green, red and carmine grow black, and white flowers turn 

 yellow. The changes of color which are most singular are 

 those shown by the flowers which have many different tints, 

 out of which the red lines become green, the white yellow, 

 etc. A remarkable example of this is seen in the fuchsias 

 having white and red flowers, and which by the action of 

 ammoniacal vapors become yellow, blue, and green. When 

 the flowers have been subjected to the changes that color 

 them, they will, if plunged in pure water, retain their new 

 colors for many hours, after which they return to their prim- 

 itive shade. Another interesting observation, due to Gab- 

 ben, is that the flowers of the aster, which are naturally in- 

 odorous, acquire an agreeable aromatic perfume under the 

 influence of ammonia. The flowers of these same asters, 

 whose natural color is violet, become red when washed with 

 diluted nitric acid. 1 -Z?, XV., 42. 



HOLLYHOCK FUNGUS. 



The hollyhocks of Europe are threatened with destruc- 

 tion by the rapid development of a fungus known as Pue- 



