330 EXPERIMENTS O^' HEMF, 



dent that very sudden thunder-showers oUcil 

 take such fiowers by surprise, the previous 

 state of the atmosphere not having been such 

 as to give them due warning. 



That parts of vegetables not only lose 

 their irritabihty, but even their vital princi- 

 ple, in consequence of having accomplished 

 the ends of their being, appears from an ex- 

 periment of Linnseus upon Hemp. This is a 

 dioscious plant, see p. 306, and Linnaius kept 

 several fertile-flowered individuals in sepa- 

 rate apartments from the barren ones, in 

 order to try whether they con id perfect their 

 seeds without the aid of pollen. Some few 

 however remained ^vith the barren-flowered 

 plants, and these ripened seed in due time, 

 their stiaimas having faded and withered soon 

 after they bad received the pollen. On the 

 contrary, the stigmas which had been out of 

 its reach continued green and vigorous, as if 

 in vain expectation, nor did they begin to 

 iiide till they had thus lasted for a ver}^ long 

 while. Since I read the history of this expe- 

 riment, I have found it easy in many plants to 

 tell by the appearance of the stigma whether 

 the seed be fertilized or not. The above ex- 



