INTRODUCTION. 



5 



to the works of man, and it often happens that too little 

 or too much rain, or other influences, as mildews and 

 insects, prove injurious to the life of plants and prevent 

 them from coming to maturity, thus causing famine and 

 death to whole districts, as instanced in India in 1866, 

 when thousands of people perished for want of food. Even 

 Great Britain and Ireland, with their highly cultivated 

 fields, are not able to produce sufficient food for the 

 29,000,000 of inhabitants ; a few more rainy days during 

 the harvest of 1866 would have caused a famine. 



Tilling, sowing, and reaping, however, are unknown to 

 many races of men, even in the most favourable climates. 

 For instance. New Holland, abounding as it does in 

 forest and grass lands, possesses no native corn, fruit, 

 or roots of sufficient succulency or abundance to form 

 a staple of food for a large population. Hence the 

 wandering habits of the natives, whose vegetable sus- 

 tenance chiefly depends on fern-root^ nardoo, Araucaria 

 nuts, and the like. 



Next in importance to food is protection from the 

 vicissitudes of heat and cold. In the broad central zone 

 of the earth where the temperature is such that man re- 

 quires no artificial protection, except for the hereditary 

 virtue of decency, many races, like our first parents, only 

 sew leaves together, or make use of pieces of bark in the 

 most primitive form, as may be seen from many speci- 

 mens in the museum at Kew. But in the earliest times 

 of civilization we find that flax was grown in Egypt. 

 Cotton also appears to have been early known, and it is 

 singular that these two substances still continue to 

 supply the materials for the chief articles of clothing. 

 It is not only to insure a regular supply of food and 

 clothing that man is stimulated to till the ground, but 



