H. BOTANY AND HORTICULTURE. 299 



neither the nitrogen compounds, iron, nor any other of these 

 eight bodies can be omitted from the fluid in question if the 

 plants are to pass through their various stages of develop- 

 ment without becoming bleached or prematurely dwarfed. 

 It is also shown by the experiments that while only these 

 eight bodies are necessary elements of our culture-plants, 

 others, found in ashes, such as silicic acid, manganese, copper, 

 fluorine, and soda, are to be considered, if not essential, at any 

 rate useful. Finally, the experiments appear to show that a 

 plant is capable of deriving the whole of the carbon necessary 

 for its growth, for the increase of its foliage, for the formation 

 of sugar, starch, etc., from the atmospheric air, in the form of 

 carbonic acid, by means of the stomata of its leaves. This 

 novel method of prosecuting investigations upon the growth 

 of plants and the formation of their tissues and components, 

 it is believed, tends much toward securing exact results in 

 such researches, and in time may enable us to acquire a thor- 

 ough knowledge of the phenomena involved. 6 (7, 1871, 

 June 1, 216. 



EXPERIMENTS ON THE GERMINATION OF SEEDS. 



Mr. Vogel, of the Bavarian Academy of Sciences, has made 

 a series of interesting experiments on the germination of seeds 

 exposed to the action of different chemicals, either in a solid 

 or a liquid condition. He found that many chemical combi- 

 nations, though absolutely insoluble in distilled water, injured 

 or destroyed the germs of seeds, and inferred that the process 

 of germination itself produces vegetable acids which then act 

 as solvents. He was actually able to determine, by sprout- 

 ing barley, clover, and water-cress, the amount of said acids, 

 which, though differing with different seeds, was always quite 

 considerable. He experimented with Prussian blue, carbon- 

 ate of magnesia, oxide and carbonate of copper, chrornate of 

 mercury, sulphur, and antimonial preparations, and, more re- 

 cently, with aniline and amorphous phosphorus, and found 

 that all these insoluble substances prevented germination, 

 either entirely or to a great extent, while the presence of 

 sublimed indigo had not the least effect. Of solutions, he 

 mentions chrornate of potash (nitrate of silver) and arsenious 

 acid as especially injurious, and states that other mineral 

 acids, when very much diluted, are less obnoxious. Remark- 



