318 REPORT OF THE CONFERENCE ON GENETICS. 
the latter bags being temporarily opened at the top to receive the pollen, 
and then closed up; every possible precaution being taken to prevent 
during the transference the access of pollen from any other source.’ ® 
It was, however, pointed out that such a method did not entirely 
prevent self-pollination, and therefore it has been replaced by others in 
which this risk is not so great. 
In 1894 it was found by Wakker, in Java, that the Cheribon cane 
did not bear fertile pollen while the pistil was normal, and therefore 
any seedling raised from this cane would be the result of cross-fertilisation. 
This was a great advance in the hybridisation problem of the sugar-cane. 
Kobus, by planting other good varieties, known to possess fertile pollen, 
by the side of this Cheribon cane, obtained thousands of seedlings as the 
result of intercrossing. Investigations in Java upon the raising of sugar- 
cane seedlings centred around this discovery, and therefore in 1902 
a large number of the best seedling canes at Barbados were examined 
by Lewton-Brain® in the Laboratory of the Imperial Department 
of Agriculture for the West Indies to inquire into the proportions of 
fertile to infertile pollen in the anthers of different varieties. By this 
means it was possible to divide the West Indian varieties of canes into 
three classes: (1) in which the anthers show a large proportion of 
normal pollen; (2) in which the anthers show a very small proportion 
of normal pollen ; (8) in which the anthers show a moderate proportion 
of normal pollen. If, therefore, an arrow of a cane producing much 
normal pollen is bagged with an arrow of a cane producing little fertile 
pollen, the risk of self-fertilisation is reduced to a minimum, and if fertile 
seeds are produced by these canes they will almost certainly be the result 
of hybridisation. 
The possibilities of the hybridisation of the sugar-cane under 
control, by removing the stamens of one flower and the transference 
of pollen from another, were discussed by Boname, Mauritius, in 1899. 
It was thought, however, that this was almost impracticable on account 
of the large number of flowers on each panicle, and also through their 
microscopic size. It was also pointed out that it was not known with 
certainty whether the flowers of the sugar-cane were autogamous or 
not, and therefore emasculation would have to take place while the 
flowers were very young. The emasculation of immature spikelets of 
the sugar-cane without injuring the very delicate ovary and stigmatic 
plumes was thought to be an operation of considerable difficulty, and 
therefore the raising of seedlings by hybridisation under control was 
dismissed as being impossible. In 1900, d’Albuquerque stated that to 
ensure that the seedling-canes produced are the result of cross-fertilisation 
between the parents selected “would need the elimination of the anthers 
before they were mature, a very difficult task in a plant the parts of 
whose flowers are so small as in the sugar-cane’”’; but in 1904, Lewton- 
Brain, after consultation with d’Albuquerque and Bovell, performed 
experiments in artificial cross-pollination, in which the flowers of one 
variety were emasculated while still young, covered in a muslin bag, 
and then pollen from another variety was transferred to them by hand. 
This method of raising hybrids by artificial cross-pollination proved 
successful. Five stools of hybrid canes were raised in Barbados as the 
