P I S U M. 
535 
The grey and other late peafe (land to ripen their feed ; 
they are then cut up with hooks, rolled into wads, 
turned once or twice, and then (tacked up. 
About one-third of the peafe cultivated in Middlefex 
and Kent is eaten by men, and the relt by hogs. The 
haulm is cut green, and dried quickly whiift in the full 
vigour of its lap, is nearly as good as hay for cattle and 
horfes. 
Mr. Knight (Phil. Tranf. 1799) made forne curious 
and fatisfaftory experiments on improving the cultivation 
of peafe by eroding the breed as it is vulgarly called ; that 
is, by introducing the farina of a different and diftinft 
fpecies into the piftils of the plants growing in his own 
garden. He has explained his mode of proceeding in a 
paper which was read before the Royal Society on the 
9th of May in that year; and we (hall conclude this 
article with a few extrafls. 
“ The breeders of animals have very long entertained 
an opinion, that confiderable advantages are obtained by 
breedingfrom males and females not related to each other, 
and I can fpeak from my own obfervation and experience, 
that animals degenerate, in fize at lead, on the fame paf- 
ture, and in other refpefts under the fame management, 
when this procefs of eroding the breed is neglefted. 
The clofe analogy between the animal and vegetable 
world, the fexual fyftem equally pervading both, induced 
me to fuppofe, that dtnilar means might be produftive of 
fimilar effefts in each ; and the event has, I think, fully 
juftified this opinion. 
“ The principal object I had in view, was to obtain 
new and improved varieties of the apple, to fupply the 
place of tbofe which have become difeafed and unpro¬ 
ductive, by having been cultivated beyond the period 
which nature appears to have adigned to their exiftence. 
But, as I forefaw that feveral years mud elapfe, before 
the fuccefs or failure of this procefs could podibly be 
afeertained, I wifhed, in the interval, to fee what would 
be its effefts on annual plants. Amongd thefe, none 
appeared fo well calculated to anfwer my purpofe as the 
common pea; not only becaufe I could obtain many va¬ 
rieties of this plant, of different forms, dzes, and colours; 
but alfo, becaufe the ftrufture of its bloffom, by prevent¬ 
ing the ingrefs of infefts and adventitious farina, has 
rendered its varieties remarkably permanent. I had a 
kind growing in my garden, which, having been long 
cultivated in the fame foil, had ceafed to be produftive, 
and did not appear to recover its former vigour, when 
removed to a foil of a different quality; on this, my 
fird experiment, in 1787, was made. Having opened a 
dozen of its immature bloffoins, I dedroyed the male 
parts, taking great care not to injure the female ones ; 
and, a few days afterwards, when the bloffoms appeared 
mature, I introduced the farina of a very large and lux¬ 
uriant grey pea into one half of the bloffoms, leaving the 
other half as they were. The pods of each grew equally 
well; but I foon perceived that, in thofe into whofe blof¬ 
foms the farina had not been introduced, the feeds re¬ 
mained nearly as they were before the bloffoms expanded, 
and in that date they withered. Thofe in the other pods 
attained maturity, but were not in any fenfible degree 
different from thofe afforded by other plants of the fame 
variety ; owing, I imagine, to the external covering of 
the feed (as I have found in other plants) being fur- 
nifhed entirely by the female. In the fucceeding fpring, 
the difference, however, became extremely obvious; for 
the plants from them rofe with exceffive luxuriance, and 
the colour of their leaves and items clearly indicated, 
that they had all exchanged their whitenefs for the 
colour of the male parent : the feeds produced in autumn 
were dark grey. By introducing the farina of another 
white variety, (or, in fome indances, by fimple culture,) I 
found this colour was eafily difeharged, [this we think ex¬ 
tremely curious,] and a numerous variety of new kinds 
produced, many of which were, in fize, and in every 
other refpeft, much fuperior to the original white kind, 
and grew with exceffive luxuriance, fome of them attain¬ 
ing the height of more than twelve feet. I had frequent 
occafion to obferve, in this plant, a ftronger tendency 
to produce purple bloffoms, and coloured feeds, than 
white ones; for, when I introduced the farina of a purple 
bloffom into a white one, the whole of the feeds in the 
fucceeding year became coloured : but, when I endea¬ 
voured to difeharge this colour, by reverfing the procefs, 
a part only of them afforded plants with white bloffoms; 
this part fometimes occupying one end of the pod, and 
and beingat other times irregularly intermixed with thofe 
which, when fown, retained their colour. It may per¬ 
haps be fuppofed, that fomething might depend on the 
quantity of farina employed; but I never could difeover, 
in this, or in any other experiment, in which fuperfeeta- 
tion did not take place, that the largeft or fmalleft quan¬ 
tity of farina afforded any difference in the effeft produced. 
“The diffimilarity I obferved in the offspring afforded 
by different kinds of farina, in thefe experiments, pointed 
out to me an eafy method of afeertaining whether fuper- 
foetation (the exiftence of which has been admitted 
amongft animals) could alfo take place in the vegetable 
world. For, as the offspring of a white pea is always 
white, unlefs the farina of a coloured kind be introduced 
into the bloffom; and as the colour of the grey one is 
always transferred to its offspring, though the female be 
white; it readily occurred tome, that, if the farina of 
both were mingled, or applied at the fame moment, the 
offspring of each could be eafily diftinguifhed. My firft 
experiment was not altogether fuccefsful; for the offspring 
of five pods (the whole which efcaped the birds) received 
their colour from the coloured male. There was, how¬ 
ever, a ftrong refemblance to the other male in the growth 
and charafter of more than one of the plants; and the 
feeds of feveral, in the autumn, very clofely refembled it 
in every thing but colour. In this experiment, I ufed 
the farina of a white pea, which poffeffed the remarkable 
property of fhrivelling exceffively when ripe ; and, in the 
fecond year, I obtained white feeds, from the grey ones 
above mentioned, perfectly fimilar to it. 
“Another fpecies of fuperfeetation (if I have juftly 
applied that term to a procefs in which one feed appears 
to have been the offspring of two males) has occurred to 
me fo often, as to remove all poffibility of doubt as to its 
exiftence. In 1797, the year after I had feen the refult 
of the laft-mentioned experiment, having prepared a great 
many white bloffoms, I introduced the farina of a white 
and that of a grey pea, nearly at the fame moment, into 
each; and as, in the laft year, the charafter of the co¬ 
loured male had prevailed, I ufed its farina more fparingly 
than that of the white one; and now almoft every pod 
afforded plants of different colours. The majority, how¬ 
ever, were white; but the charafters of the two kinds 
were not fufficiently diftinft to allow me to judge with 
precifion, whether any of the feeds produced were of 
common parentage or not. In the laft year, I was more 
fortunate : having prepared bloffoms of the little early 
frame-pea, I introduced its own farina, and immediately 
afterwards that of a very large and late grey kind, and I 
fowed the feeds thus obtained in the end of the laft Cum¬ 
mer. Many of them retained the colour and charafter of 
the fmall early pea, not in the flighted degree altered, and 
bloffomed before they were eighteen inches high ; whiift 
others, (taken from the fame pods,) whofe colour was 
changed, grew to the height of more than four feet, and 
were killed by the froft, before any bloffoms appeared. 
It is evident, that in thefe inftances fuperfeetation took 
place; and it is equally evident, that the feeds were not 
all of common parentage. Should fubfequent experience 
evince that a lingle plant may be the offspring of two 
males, the analogy between animal and vegetable nature 
may induce fome curious conjefture relative to the pro¬ 
cefs of generation in the animal world. 
“ In the courfe of the preceding experiments, I could 
never obferve that the charafter, either of the male or 
female, 
