290 PAEA.SIXISM IN PLANTS AND ANIMALS. 



benefit by absorbing a part of tlie dissolved starch, and from the 

 digestion of the dead bodies of the algse. On the other hand the 

 carbonic acid and nitrogenous waste produced by the animal cell 

 constitute the nutritive return made to the alga, which in remov- 

 ing them performs the function of a kidney. 



" Thus, then, for a vegetable cell no more ideal existence can 

 be imagined than that within the body of an animal cell of suffi- 

 cient active vitality to manure it with abundance of carbonic acid 

 and nitrogenous waste, yet of sufficient transparency to allow the 

 entrance of the necessary light. And, conversely, for an animal 

 cell there can be no more ideal existence than to contain a suffi- 

 cient number of vegetable cells, constantly removing its waste 

 products, supplying it with oxygen and starch and being diges- 

 tible after death." 



We see, then, that parasitism fills a very large space in the 

 economy of nature, but we may recognize at the same time that 

 it is not an unmixed evil, — that the creatures preyed upon gene- 

 rally possess a reserve of vitality sufficient to protect them, for 

 a long time at any rate, from serious disaster, and that in the 

 most confirmed cases the ill-results are often even more apparent 

 in the parasite itself than in the animal attacked. May I draw 

 a " parable from nature" and say that thus it must be morally 

 even amongst ourselves, that those who look to the activities of 

 their neighbours for support — the incurably idle, thieves and 

 gamblers, — undergo a constantly progressive degradation of their 

 moral nature ? 



And if we give a little play to fancy, may we not say that 

 we ourselves — the whole human race — are but parasites on the 

 bosom of our mother Earth, draining the juices which slie boun- 

 tifully supplies, she, who we may rightly regard but as our 

 intermediate host. For who can say but that the Poet's words 

 may be true, — 



Our birth is but a sleep and a forgetting, 

 The soul that rises with us, our life's star, 



Hath had elsewhere its setting, 

 And coraeth from afar. 



However this may be, we are permeated with tlie faith that 



