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bility^ in other words, amongst which there can, for a great 
number 6f genetic factors be found individuals or types having 
them and öthers without them. 
Such is the case with maize, with the horse, wheat, dogs 
peas and swine^ sheep and pouJtry. Let us examine wheat^ wich 
is next to the dog perhaps the best example. Among the 
fourteenhundred pure types of wheat in the collection of the seed- 
firm Vilmorin-Andrieux^ there are only a few more than 
a dozen which can be profitably grown around Paris. All the 
others have combinations öf factors which make, that under the 
cunditions under which wheat is grown here, they can not 
compete with the first dozen. But this does not mean that these 
few varieties of wheat are therefore the best generally. They 
are simply the most profitable here. The iudividual adaptation of 
all the other types and a little study as to some special condi- 
tions they may require, suffice to make it possible that they are 
all grown at Verrieres. It would be possible among such a 
collection to find wheats^ which there are only kept for curiositys 
sake^ but which would be excellent in some other part of the 
world^ with a longer or shorter season, with a greater or lesser 
rainfall, with an abnormally wet or very severe winter, or with 
an exceptionally hot summer. A combination of genetic factors 
which in France or in Sweden gives undesirable characters, may 
in Thibet or in New South Wales prove to be just the thing 
required. Thus may long glumes be looked upon as undesirable 
in countries where they have no use whatever, and only serve 
to heighten the chance to catch rust or smutspores, whereas in 
countries with an excessively hot summer like Thibet or Okla- 
homa long glumes may protect the young grains from the withering 
effect of hot winds. In countries with a rainfall limited to one 
season like California, it will be necessary to choose ainongst 
rapidly-stocking summerwheats, which would in Western Europe 
be unable to compete whith slow-growing winterwheats. 
Sometimes there are very special conditions under which 
it would seem impossible to grow wheat, and it is so mething 
astonishing to see how some varieties can under them give a 
paying crop. Thus there exists a variety, „hatif de la Saone" 
which can be grown on land standing under water for weeks 
at the time. This is again a good instance of the relative cost 
of the manipulating of the genetic Constitution, and the maui- 
