148 Transactions. 
70 deg. (north latitude) to 65 deg. in Scotland, in Ireland to 
52 deg.; the north and south limits of this zone being determined 
according to the varying distances of the sea. 
The zone of rye occupies the greater part of Europe north of 
the Alps ; but on the west side wheat is the predominant bread- 
stuff. 
The zone of wheat extends from the boundary of the zone of 
rye (50° to 58° north latitude) southwards to the African desert, 
including, besides Great Britain and France, the whole of southern 
Europe and the north of Africa. 
Rice (Oryza Sativa) supplies food to a much greater number 
of the human race than any other cereal. Throughout China, 
India, and many other regions of Asia and of Africa, it forms the 
principal and almost the only food of the people. It is less 
nutritive than any of the cereal grains. About 40 or 50 varieties 
of rice are known and cultivated. Rice is a marsh plant, and can 
only be successfully grown where the ground may be inundated 
during the early period of its growth ; it requires also a higher 
temperature than the others, excepting maize. Its highest northern 
limit in Europe is Lombardy, where maize is also grown. 
Maize or Indian corn (Zea mays) ranks next to rice in the 
number of human beings it feeds. Systematists make of the 
genus to which it belongs five species, all of which are natives of 
South America. Indian corn is now cultivated in every quarter 
of the globe. It is largely consumed in England, nearly four 
millions of quarters having been introduced into this country 
annually in the beginning of the current decade, and there has 
certainly been no diminution since. Polenta or maize meal 
porridge has become almost the national dish of the Italian 
peasantry. Maize is considered the most fattening of all the 
cereals. 
Besides these staple grain-producing grasses, there are a number 
of others, scarcely, if at all known in England, which furnish 
food to populous communities abroad. Among these are several 
species of Holcus. The seeds of Holcus succharatum, somewhat 
extensively used for sugar-making, are eaten in Africa under the 
name of dochna. Holcus Sorghum produces a grain largely 
employed as food in Africa and other countries under the names 
of Guinea corn, duna, and Turkish millet. It has been employed 
in this country for feeding poultry. In the Soudan the German 
naturalist, Werner, found this grain with stalks fifteen and twenty 
