DISHARMONIES AND OTHER SHADOWS 583 



defence against it. Similarly, the tsetse-fly transfers the 

 trypanosome from some immune wild animal (such as an 

 antelope, it may be) to the highly susceptible man. But 

 these microbes are not in any special way adapted to parasitic 

 life; they might as well be called predatory. Many preda- 

 tory parasites, like Trypanosomes, live an exceedingly active 

 life within their host, exerting themselves as much as many 

 a free-living creature. 



(2) Many parasites are aesthetically repulsive in form, 

 colour, and movements, and it is interesting to contrast the 

 attractive free stages of some of them with the ungraceful 

 bloated parasitic stages. As we have already seen, the ugli- 

 ness is the brand of their degeneracy. It is the natural re- 

 sult of retrogression, sluggishness, and over-feeding. The 

 life of ease drifts and it loses the grace of the sharpened 

 life which commands its course. The dodder and mistletoe, 

 which every one must admit to be beautiful, are, it is inter- 

 esting to notice, only partial parasites. The ugliness of 

 some parasites is perhaps an exception that proves the rule ; 

 it is as if Nature said : This asylum is open, if you will, but 

 if you enter, you must wear the livery of dishonour ; beauty 

 will disappear. 



(3) To many minds, however, the darkness of the shadow 

 is in the inconsistency between the parasitic mode of life 

 and Nature's usual insistence on a strenuous life, and this 

 has to be admitted. But one must remember how parasitism 

 arises in the struggle for existence. Environing limitations 

 and difficulties press upon the organism and one of the solu- 

 tions which is open to many is to evade the struggle by 

 becoming parasitic. The struggling, endeavouring creature 

 cannot have a clear prevision of the facilis descensus it has 

 set foot on. It may try to survive inside a larger organism 



