31:; 



THE EVOLUTION OF LIFE. 



lower order. So long, too, as we leave out all mortality but 

 that wliicli, by carrying oS the least perfect members of each 

 species, leaves the most perfect members to continue the 

 Bpecies ; we see some compensating benefit reached through 

 the suffering inflicted. But what shall we say on finding 

 innumerable cases in which the suffering inflicted brings no 

 compensating benefit ? What shall we say when we see the 

 inferior destroying the superior ? "What shall we say on 

 dJscovoriag elaborate apj)liances for securing the prosperity 

 of organisms incapable of feeling, at the expense of misery 

 to organisms capable of happiness ? 



Of the animal kingdom as a whole, more than half tlio 

 species are parasites. " The number of these parasites," 

 says Prof. Owen, " may be conceived when it is stated that 

 almost every kno^vn anunal has its peculiar species, and 

 generally more than one, sometimes as many as, or even 

 more lands than, infest the human body." Passing over the 

 evils thus inflicted on animals of inferior dignity, let us limit 

 ourselves to the case of man. The Sothrioccp/ialus latus 

 and the Tcenia solium, are two kinds of tape-worm, which 

 flourish in the human intestines ; producing great constitu- 

 tional disturbances, sometimes ending in insanity ; and from 

 the germs of the Tcenia, when carried into other parts of the 

 body, arise certain partially-developed forms kno'mi as" Cysti- 

 cerci, Echinococci, and Canuri, which cause disorganization 

 more or less extensive in the brain, the lungs, the liver, 

 the heart, the eye, &e., often ending fatally after long- 

 continued suffering. Five other parasites, belonging to 

 a different class, are foimd in the viscera of man — the 

 Triclioceplialiis, the Oxyuris, the Strovgylus (two species), 

 Ihe Ancylostomum, and the A'icaris ; which, beyond that 

 defect of nutrition which they necessarily cause, sometimea 

 induce certain irritations that lead to complete demoraliza- 

 tion. Of another class of entozoa, belonging to the sub- 

 division Tremcdoda, there are five kinds found in differert 

 organs of the human body — the liver and gall ducts, the 



