184 THE KINGDOM OF MAN 



needful for pursuing these enquiries are not numerous ; 

 and those who exist are not endowed with private 

 fortunes, as a rule. At the same time no attempt is 

 made by the British Government to take such men 

 into its pay, or to provide for the training and selection 

 of such officers. 1 



The relations of parasites to the organisms upon or in 

 which they are parasitic, and the relation of man, once 

 entered on the first steps of his career of civilisation, to 

 the world of parasites, form one of the most instructive 

 and fascinating chapters of natural history. It cannot 

 be fully written yet, but already some of the conclusions 

 to which the student is led in examining this subject have 

 far-reaching importance and touch upon great general 

 principles in an unexpected manner. 



Before the arrival of man the would-be controller, 

 the disturber of Nature the adjustment of living things 

 to their surrounding conditions and to one another has a 

 certain appearance of perfection. Natural selection and 

 the survival of the fittest in the struggle for existence 

 lead to the production of a degree of efficiency and 

 harmonious interaction of the units of the living world, 

 which, being based on the inexorable destruction of what 

 is inadequate and inharmonious as soon as it appears, 

 result in a smooth and orderly working of the great 

 machine, and the continuance by heredity of efficiency 

 and a high degree of individual perfection. 



Parasites, whether microscopic or of larger size, are 

 not, in such circumstances, the cause of widespread 

 disease or suffering. The weakly members of a species 

 may be destroyed by parasites, as others are destroyed 

 by beasts of prey ; but the general community of the 

 species, thus weeded, is benefited by the operation. In 

 1 See footnote on p. 179. 



