ON RECENT DEVELOPMENTS IN AGRICULTURAL SCIENCE, 28h 
obtaining information on this point. Returning, however, to the question 
of variety, it is generally recognised that relative immunity or susceptibility 
to an attack of yellow rust is characteristic of particular varieties, and 
Biffen finds that such ‘immunity’ is a true Mendelian character, recessive 
and therefore only appearing in the second generation of hybrids between 
a rusting and a rust-proof parent. It is not correlated with shape or 
character of the leaf, but is transmitted from one generation to another 
quite independently, and can therefore be picked out of a desirable 
arent and combined with other qualities of value in different parents. 
es again, we are dealing with a character that is only relative, for no 
wheat can be called either absolutely rust-proof or entirely susceptible ; 
the offspring that have inherited immunity will still vary a trifle among 
themselves in the degree of their resistance to attack, and in this possi- 
bility of variation lies the chance of the plant: breeder to improve upon 
the rust-resisting powers of the varieties we now possess. 
The whole work of the plant-breeder is of singular importance in a 
country like South Africa whose agricultural history is so recent. Our 
European crops represent the culminating points of a tradition, and are 
the fruit of the observation and judgment of many generations of prac- 
tical men working, as a rule, with chance material. The products are 
eminently suited to European conditions, but, as has been seen so often, 
they fail comparatively when brought into other climates and soils. It 
follows, then, that in a new country the work of the acclimatiser is one of 
the necessary foundations for agriculture, and this involves a careful study 
of climatology and of the influence that the distribution of rainfall and 
temperature in various parts of the country has on the character of the 
crop. 
Then the cross-breeder’s work begins : acclimatisation alone is hardly 
likely to yield the ideal plant, but by it are found plants possessing the 
features, one here and one there, that are desiderated ; and starting with 
this ground material the hybridiser can eventually turn out an individual 
possessing in a large measure all the qualities that are sought for. 
There is little hope that science can do anything wholly new for agri- 
culture ; acclimatisation, breeding, and selection have been the mainstay 
of farming progress since the beginning of time, just as the action of the 
nitrifying bacteria and of nitrogen fixation by the leguminous plants 
were instinctively apprehended by the earliest farmers of whom we have 
any record. 
But with increasing knowledge comes more power, and particularly the 
possibility of accelerating the rate of progress ; agricultural improvements 
in the past have resulted from the gradual and unorganised accretions of 
the observation and experience of many men, often of many generations, 
now that we are provided by science with guiding hypotheses and by the 
organisation of experiment with the means of replacing casual opinions 
by exact knowledge. Even the properties of the soil and the character of 
our farm crops and animals—stubborn facts as they are and deeply 
grounded in the nature of things—ought to become increasingly plastic in 
our hands. 
