9? Account of fome Experiments on 



place of thofe which have become difeafed and unprodu(3ifr4f 

 by having been cultivated beyond the period which nature 

 appears to have affigned to their exiftence. But, as I forefaw 

 that feveral years miift elapfe before the fuccefs or failure of 

 this procefs could poffibly be afcertained, I wifl>edj in tha 

 interval, to fee what would be its effefts on annual plants. 

 Amongft thefe, none appeared fo well calculated to anfwer 

 my purpofe as the common pea ; not only becaufe I could 

 obtain many varieties of this plant, of different forms, fizes, 

 and colours j but alfo, becaufe the ftrudture of its bloflbm, 

 by preventing the ingrefs of infects and adventitious farina, 

 has rendered its varieties remarkably permanent. I had a 

 kind growing in my garden, which, having been long culti- 

 vated in the fame foil, had ceafed to be produ6live, and did 

 iiot appear to recover the whole of its former vigour, when 

 removed to a foil of a fomewhat different quality; on this, 

 my firft experiment, in 1787, was made. Having opened a 

 dozen of its immature blolToms, I deflroyed the male parts, 

 taking great care not to injure the female ones; and, a few 

 days aftervvards, when the blofToms appeared mature, I in- 

 troduced the farina of a very large and luxuriant gray pea 

 into one half of the blofToms, leaving the other half as they 

 were. The pods of each grew equally well ; but I foon per- 

 ceived that in thofe irito whofe blollbms the farina had noi 

 been introduced, the, feeds remained nearly as they were be- 

 fore the blofToms expanded, and in that ftate they withered, 

 Thofe in the other pods attained maturity, but were not in 

 any fenfible degree diflerent fronl thofe afforded by other 

 plants of the fame variety ; owing, I imagine, to .the ex- 

 ternal covering of the feed (as I have found in other plants) 

 being furnifhed entirely by the female. In the fucceeding 

 fpring, the difference, hovv^e^erj became extremely obvious ; 

 for the plants from them rofe with exceflive laturiance, and 

 the colour of their leaves and ftemS clearly indicated that 

 they had all exchanged their whitenefs fot the c»lour of 

 the male parent j the leeds produced in autumn were dark 

 gray. By introdueii>g the farina of another ivhlte variety, 

 (or, in fome infiances, by fimple culture,) I found this colour 

 was eafily difchargedy and a numerous variety of new kinds 



produe«d. 



